What, their CPUs will overheat? I've run infinite loops on cellphones lots of times without that happening. In fact, I'm running four of them right now, and have been for the last five minutes as I write this comment. The battery drain is annoying but I haven't seen instability. I've run plenty of compiles on cellphones (things like BLAS and Numpy) that take longer than that, and I've never seen one crash a phone.
If you actually do that you're going to crash a lot of cellphones and people will rightly blame your app for being badly coded.