It could be deliverymen, repairmen/handymen, plumbers/electricians, cable/phone installers--any occupation that gives that kind of mobility, and who could blend into the background.
This sniper becomes "something" utility man, etc. only when we insert the unusual vehicle.
Inserting an unusual vehicle for a get away seems to act "against" anything the snipers are doing. It makes them visible not invisible.
A guy in green khackis, sweatshirt and backpack.
Sac