With people being in your space, I have never had too much of an issue, most people dont want to crowd in on a stranger in my experience, but if they seem to be in your space smile real big and step into theirs with your arms wide. The smile is key, and be polite. Say something to the effect of, if everyone could please take one large step back in case my ball tries to escape I dont want him knocking into one of you in his attempt to get away
. The motion of moving into their space will get them to move away and the smile and joke helps ease the awkwardness of it.
As far as kids go, I dont think there is one good answer. You just gota wing it. A big smile and a polite, "please dont touch that" is usually enough to stop them from grabbing at your stuff. I usually just like answering kids with questions. "Are you a wizard?" "Do you think I am?" "NO!" "Really? Then I dont know how it is I am doing this."
Kids are tough, you just gota be patient above all else, and polite, and smile when dealing with kids. Getting on their level and showing them closely what you are doing will usually make parents happy and maybe will put a few extra bucks in your hat.
O right, I guess winter is here now. http://www.sphereocity.com/