So if you’re running iOS 17 you might have wondered why every once in a while when on the move (or using Maps to give you directions), you’ll get some annoying prompt out of the blue asking if you want to use check in. If you’re like me, chances are in the heat of the moment (eg. while starting to drive) you’ll tap on the wrong thing and end up in Messages on the verge of setting up some kind of check in with your spouse or similar. And don’t believe canceling will shut off such prompts or even give you the option to shut them off, no it will just keep doing that!
Annoyingly, Apple also does not have any Messages setting or otherwise to clearly shut off this malarky. A colleague of mine who recently almost ran her car off the bridge because she was wrestling with trying to undo such a checkin (and yes, of course she shouldn’t have been manipulating her iPhone while driving!) started harassing our department’s iOS guy about it. He claims that there is kind of a toggle for this.
Settings > Messages > Siri & Search > Suggestions > turn them all off
I have no idea if this actually works. I turned them all off but since it wasn’t clear to me before what exactly would consistently trigger those annoying check in prompts, I can’t say for sure if the fact that I haven’t had one since is proof that his advice works.
If anybody knows for sure that it does, or that it doesn’t (but what actually would shut off this nonsense), I’d love to hear about it. If indeed this works, I guess my take home message will be something along the lines of: if you can’t find an explicit toggle for a certain “feature”, go find the Siri section for the closest related topic and turn everything there off. 
Having useless gimmicks thrust in your face with no option to turn it off is really frustrating. Disappointing, Apple.