Stationing them at gas stations and schools would seem to me to make a lot of sense Stationing national guardsmen at gas stations? What are you doing, offering the perps some more stationary targets? You need snipers out in the parks away from the gas stations, not standing at the pumps as targets.
They don't have to stand at the pump as targets. They can be told to keep moving, and they can be stationed in groups of two or three (with orders to start taking photos if anything untoward happens.)