A hotel group operating in Phuket, Koh Samui, and Chiang Mai has a messaging problem that most platforms do not design for. Its Thai guests expect to hear from it on LINE, Thailand's dominant super-app with approximately 56 million monthly active users and an open rate for business messages that exceeds 90%. Its international guests, arriving from Europe, Australia, China, the Middle East, and North America, expect WhatsApp, the app that was on their phone long before they landed in Thailand. SMS sits underneath both as the guaranteed-delivery layer for OTPs, booking confirmations, and critical operational alerts. And since October 2025, the National Broadcasting and Telecommunications Commission (NBTC) has required operators to flag international SMS with an alert symbol before delivery, which means unregistered international SMS increasingly arrives looking like a potential scam warning rather than a trusted hotel confirmation.