How to leverage SMS bulk marketing to increase return visits

Welcome to the Purple technical briefing series. I'm going to walk you through how SMS bulk marketing, when built on top of your guest WiFi infrastructure, becomes one of the most cost-effective channels you have for driving return visits. Let me set the scene. You're running a venue - a hotel, a retail chain, a stadium, or a conference centre. Every day, hundreds or thousands of people connect to your WiFi. They hand over their phone number at the login screen. And then... most operators do nothing with it. That's the gap we're going to close today. First, let's talk about why SMS is worth your attention in 2026. The open rate for SMS sits at 98%, according to Forbes. Compare that to email, which averages around 20%. 90% of text messages are read within five minutes of receipt. And the ROI? Studies from Upcity put it at between 21 and 41 pounds returned for every pound spent. That's not a marginal improvement over email. That's a structural advantage. But here's the thing most marketing teams miss. The value of SMS bulk marketing isn't just in the channel itself. It's in the quality of the data feeding it. A phone number captured at a WiFi login portal is verified. The guest physically typed it in to get online. That's first-party data with a consent trail attached. It's worth considerably more than a scraped list or a third-party audience segment. Now let's get into the architecture. How does this actually work end to end? The flow has five stages. Stage one: the guest connects to your WiFi via a captive portal. This is the login page they see before they get internet access. Purple's Capture plan presents that portal on hardware from Cisco Meraki, HPE Aruba, Ruckus, Juniper Mist, Ubiquiti UniFi, Cambium, Extreme, or Fortinet - whichever you're already running. You don't rip and replace your network. Purple sits as a cloud overlay on top of it. Stage two: the captive portal collects the guest's phone number alongside an explicit SMS marketing opt-in. This is a separate checkbox from the WiFi terms of service. Under GDPR Article 6, you need a lawful basis for processing. Consent is the cleanest basis for marketing. So the opt-in must be granular, specific, and freely given. Purple's Capture flow handles this by design, with a pre-built consent mechanism that meets GDPR, CCPA, and Cyber Essentials requirements. Stage three: that phone number lands in your Purple Engage CRM, tagged with venue, visit date, visit frequency, and any other attributes you've configured. The data is encrypted at rest. Retention policies are configurable. You own the data. Purple processes it on your behalf as a data processor under a GDPR-compliant data processing agreement. Stage four: you build your SMS campaign in Purple Engage. You define the audience segment - say, guests who visited more than 30 days ago, at your Manchester venue, who haven't returned. You write the message. You schedule the send. Purple's bulk SMS engine dispatches it through carrier-grade infrastructure with delivery receipts, opt-out handling, and bounce management built in. Stage five: the guest receives the message, clicks through, and returns. You track that return visit because they reconnect to your WiFi. The loop closes. You have attribution. That five-stage loop is what separates WiFi-sourced SMS from bought lists. You have venue-level context, visit history, and a verified number. That's the data set that makes segmentation meaningful. Let me give you two concrete implementation scenarios, because theory only takes you so far. Scenario one: a 350-room hotel group with 12 properties. They're running HPE Aruba access points, already on Purple's Connect plan. The challenge: guests check out and never come back. Average return rate is under 8% within 12 months. They move to Purple's Engage plan. They configure the captive portal to capture phone numbers with an SMS opt-in. Within 90 days they've built a database of 14,000 consented mobile numbers across the estate. They run three campaigns. First: a win-back campaign targeting guests who stayed more than 60 days ago, offering a 15% loyalty rate. Open rate: 94%. Redemption rate: 11%. Second: a local event campaign, targeting guests who stayed within 20 miles of a specific property, promoting a weekend package. Third: a post-stay feedback request with a discount code for the next booking. The net result after six months: return visit rate up from 8% to 19%. Revenue per available room up by 6.2%. Scenario two: a retail chain with 45 stores across the UK. They're on Cisco Meraki with Purple Capture already deployed for footfall analytics. The marketing team wants to use the WiFi data for re-engagement but has been blocked by the legal team over GDPR concerns. The fix is straightforward. Purple's consent flow is updated to include a specific SMS marketing opt-in, separate from the WiFi access terms. Legal reviews and approves the consent language. The data processing agreement is updated. Within eight weeks they're running their first bulk SMS campaign. They segment by store visited, purchase category inferred from dwell time near product zones, and visit recency. The campaign drives a 23% uplift in return visits among the targeted segment versus a control group that received no message. Now let me flag the pitfalls, because there are a few that catch teams out. Pitfall one: conflating WiFi consent with SMS consent. Connecting to your WiFi does not constitute consent to receive marketing messages. These are two separate legal bases. Your captive portal must present them as two separate choices. If you bundle them, you're non-compliant under GDPR and exposed to ICO enforcement. Pitfall two: sending too frequently. SMS is a high-attention channel. That's its strength. But it's also why overuse destroys it. Industry benchmarks suggest no more than four to six messages per month per contact. Above that, opt-out rates climb sharply. Purple Engage lets you set frequency caps per contact to prevent this automatically. Pitfall three: ignoring delivery infrastructure. Not all bulk SMS providers are equal. Carrier routing, sender ID registration, and throughput limits vary significantly. If you're sending to 50,000 contacts simultaneously, you need a provider with sufficient throughput and carrier relationships to avoid message queuing and delivery delays that undermine time-sensitive offers. Pitfall four: no attribution loop. Sending SMS campaigns without closing the attribution loop is a waste of budget. If you can't tie a return visit back to a specific campaign, you can't optimise. Purple's WiFi reconnection tracking gives you that loop automatically. When a guest who received your campaign reconnects to your WiFi, that visit is tagged against the campaign. Right, let's do a rapid-fire question and answer on the most common things I get asked. Question: do we need to replace our existing network hardware? No. Purple deploys as a cloud overlay. Your Cisco Meraki, Aruba, or Ruckus kit stays in place. Question: how long does it take to build a usable SMS database? With active footfall, most venues reach 10,000 consented numbers within 60 to 90 days. Question: what's the minimum viable segment size for a bulk SMS campaign? Practically, 500 contacts. Below that, statistical significance is low and the cost-per-insight is high. Question: can we integrate Purple's data with our existing CRM? Yes. Purple Engage has API connectors and webhook support for standard CRM platforms. Question: what happens when someone opts out? Purple's engine processes opt-outs in real time and suppresses that number from all future sends automatically. You are never at risk of messaging a contact who has unsubscribed. To wrap up. The case for SMS bulk marketing built on guest WiFi data is straightforward. You have a verified, consented, venue-contextualised phone number database that most operators are sitting on and not using. SMS delivers a 98% open rate and up to 41 pounds return per pound spent. The compliance framework is manageable if you separate WiFi consent from SMS consent and document your retention policy. And the attribution loop - WiFi reconnection tracking - gives you the measurement infrastructure to optimise campaigns over time. The practical starting point is Purple's Engage plan. Capture the data at the portal, segment by visit recency and venue, and run your first win-back campaign within 30 days of go-live. That's the fastest path to measurable return visit uplift. Thanks for listening. If you want to see this in action across your estate, the Purple team can walk you through a live demo. Details are in the guide linked below.