Also if you end up in a kidnapped or murdered situation, then (hopefully) your parents are going to get law enforcement involved as soon as you've been out of contact for a scary amount of time, and law enforcement has ways to find your phone even if tracking's not on.

(Before that point it's going to be counterproductive, because if Mom calls the cops every time you go to a park you've never visited before and don't immediately text her back, they aren't going to pay attention the next time she calls.)