There is a boy on Son's baseball team whose sisters I hate. They're twins, around DD1's age, I'm guessing a little older. They've been in the league for several years and we've always lucked out not having this boy on our team (because DH was always the coach until this year and the boy wasn't very good, so DH never picked him).
These girls have no boundaries. Their mom waits until they've dug through my diaper bag before she'll come get them and lead them back over to her seat. I've only let them do it once and I was just shocked that there were these two little girls digging snacks and toys out of my bag. They've attempted to go through my stuff every year (when our team plays theirs) and I always ask them not to do it and to go find their mommy. Now they're on our team and we see them 3-4 nights per week.
I am more than happy to share our stuff with others. In fact, I always bring extra stuff for that reason. But I don't want their snotty little hands in my bag and I don't appreciate their mom letting them roam the park and do whatever the hell they want and go through people's things. The ballpark is not a babysitter because you're tired. I shouldn't be expected to entertain your children.
Also, one day they offered DD1 gum and DD1 declined, telling them that she isn't allowed to have it. One of the little girls told her to just spit it out before she gets home so her parents don't find out. DH HEARD THEM TELLING HER THIS.
I know hating children makes me a horrible person, and I should hate the mom (which I do) and not the kids because it's not their fault, but I can't help it. I would be mortified if my kids were like this.