I worked in telecom for a couple of years up until recently. There’s actually a growing body of self-regulation going on within the SMS industry. Most notably, any business sending text messages has to apply for a “license” to do so, with some pretty strict consent requirements. Violating those requirements comes with heavy penalties, mostly enforced by downstream carriers. If you’re curious, 10DLC/A2P are the terms to Google for.

Does anyone have the recipe on hand? I’m curious what it actually recommended but I couldn’t find it with a cursory Google search

Ditto. I mostly use it when Google (search, not Bard) fails me. I find it’s really good at answering questions of the ilk: “I swear there’s a function for this in the library I’m using, what’s it called again?”, or telling me that it doesn’t actually exist.