Tracking a kid at an amusement park, presumably a quite young one, is entirely fine IMO. I remember when I was 4 or so, I waited until my parents weren't looking to sneak off and go play with a toy in the gift shop my parents didn't let me see earlier in the day. I just about gave them a heart attack.
Yeah it is important to know where your kids are. I go with "pay attention".
I guess there are going to be scenarios where tracking could help and maybe even allow the kids freedom to roam within a large zone - the back paddock of a farm say - while still allowing parents to find them.
Some people have more children than adults. “Pay attention” is the default state but it’s not always possible to pay complete attention to both children and everything else, every moment of every day.
I really think you’re holding parents to an unreasonably high standard. The punishment for a moments lapse in not paying attention shouldn’t be a missing 4 year old.