I'll start by saying I'm not a parent. I don't pretend to be able to tell you all how to do your job. In fact, I watch my nephew just one day a week, and I see how hard it is, how tiring, and how wonderful - and he's only 8 months old! He's not even running around yet, or talking.
So I get it, and I won't pretend to know more than you parents.
I do notice things, though.
I consider my area as a face painter to be a "good manners" zone. When I tell kids to refrain from leaning on my table, I expect them to listen. I completely understand them forgetting, and know how tempting it is to lean - I'm a leaner myself. So I'm not worried about those kids. But I've had the occasional event where the kids set out to disobey, and purposely shake my table, which is a light aluminum camping table, just to be contrary.
I've seen kids try to cut in line and shove other kids around, and I'll quickly let them know that no one who misbehaves is eligible to be painted.
I tell kids who curse that they need to stop or they won't get painted.
My space, my rules. And I refuse to reward bad behavior.
Apparently, despite my inexperience, I'm doing things right. According to this article, parents really do need to be the boss. I personally see that as extending to all adults in authority - teachers, coaches, and yes, face painters. No, I'm not about to take over your job. And I'm not about to tell you you're doing it wrong. But the author of this article does seem to have some good thoughts on the subject. The blog in general is a useful resource. Hope it helps someone out there reading this.