Age play and uniform

There are a number of advantages to the wearing of school uniform that as someone who was subject to it can recall such as the ease of being able to tell which school you belonged to if you were caught 'up to no good' by either other folk or your teachers going across your town or village.

Another one of things is that, especially when you got older you still looked like a child even if your build had shall we say developed so nobody was in any doubt you were a child and so you were dealt with as one not as a young man or woman who'd just got a job locally.
That sense is why in an age play context, being in at least children's clothes if not actual school uniform just works as it shrinks you and places you in that postion and role as that child.