Mysty,
When my son was young and visiting dad I always managed to be friends with the woman he was seeing, because SHE was the one that would end up responsible. The only thing wrong with these woman was their choice in men. Other than that they made she the Beav stayed ok.
Other wise I think the kids need to have two phone numbers on them all the time. Your girlfriends and yours. I am beginning to teach my 5 year old grandson that he can ALWAYS call PaPa or me! No matter what!
And they should be told they can say "NO" if they don't feel safe. Like getting in the car for instance.
Hugs,
JT