I HATE that! I usually cough a bit and say, "Not too close, I have a cold." That almost always works. The bad thing is, I really hate it when its children who get too close, I do NOT want to be touched and other people's children make me uncomfortable. I guess I'm more afraid the parent will get angry if I accidentally trip over their kid.
I like my bubble, but sometimes I let Hubby in, After all, just 20 short years ago, Hubby was a stranger!
I always let my kids in for hugs and cuddles!