I don't think if they recruit in public schools that would make problem to whoever might see that, as i don't think that the military would. If it's necessary to recruit what would cause damage more ?
Anyway such a view like that in public might be lesson and also might makes every body feels safe as well.
I don't agree with the military recruiting in public schools because I think that they try to single out the underachievers and persuade them at an age which they are possibly not even completely mature emotionally to put their lives in danger. I think they would be better off letting interested people coming to them because some people might join to try to impress their friends and then later realize they made a big mistake.