Older people are so behind the times. Pokemon Go will be dead this time next month, and even if a rare Pokemon spawns down the street you can still touch it without entering a school.
I find it so annoying when older people want to control and legislate everything. It's a huge problem in France right now.
I think she has a point though.
Let's say there appears an Articuno on some school's premises during class. Not only would children flip their shit, probably skipping class to be able to catch it, it would also attract many outsiders who can cause disturbances and probably even worse problems.
No rare/legendary Pokémon at schools is actually a very good idea. This game dictates to many people's lives already.
Articuno won't appear, and by the time the school year really gets going, children will already have almost every rare Pokemon. You only need one of each rare Pokemon; it's not like this game has unlimited opportunities. It has an expiry date.
Also, Pokemon Go is dead and children will have moved on by the time anyone plans these fences.
Also, Niantic can't even code their own game properly, how will they be able to prevent spawns in certain areas? Especially by using their shitty implementation of the Google Maps API? This isn't even feasible.