"Pretend like I'm not here"

That's what I say to kids when I have an assignment around them: "pretend like I'm not here, okay?" Because I don't really want them to look at me, or give me a big smile, or throw up some kind of gang sign ... yeah, that's happened before, damn near killed myself laughing so hard ... And then there are the people who aren't really looking at you, which might run ...