Well next time pay closer attention yourself, they are either firmly mounted, or they are designed to be very noticeable or untribable, like with backs on them.
You haven’t noticed it, because of the codes and standards, but of course negligence can always happen, like someone moving a bench (which shouldn’t be movable in a place with children) and put it where it shouldn’t be.
Also, you think your daycare is gonna admit they moved something and let your kid trip? Nah, they’ll blame the kid instead of wanting their business to look bad. Anyone who’s been around kids know have a very good memory as well, so when they trip over something, it probably wasn’t there 5 minutes ago as well.
It’s a little more interesting than this even. Your brain knows the stair riser heights after 2-3 steps, so individual stairs can be different riser heights, 125-200mm (5-8”). Each riser can’t be more than 3mm different in an individual stair. Not uncommon for your upper stairs to be slightly different from the bottom if there’s a landing.
So those people do consciously need to remember step 15 is different or they can trip. The rest would be pretty normal.