personally I would make her cancel, these are your snakes, not hers, if she insists on it, print out a form basicly explaining everything, and saying that if the child gets bit then you are not responsible for it. And if the childrens parents do not sign this, then they can pet the snake while you are holding her/his head. If the parents sign the paper, then show each child individually how to hold the snake, and limit the amount of time holding the snake to about 1-2 min a piece.......then afterwords.......tell your gf to have enough respect to ask you first.......I'm sure she wouldn't want you to take a few kids and have them handling her fave......jewlry, stuffed animals, porclin dolls.......anything of hers that she is protective over........Just my 2 cents.....please don't take offence!!! and goodluck.
Neptune, Zion, Enigma,