Meh. I don't mind paying for an autograph that's benefiting charity. I won't pay more than $10, though, so that limits who I can get.
As far as the kids go, I think it's a teaching opportunity. At some point they have to letting that players don't owe them an autograph. Would it be nice? Absolutely. But not every player is Mike Trout, who allegedly signs a lot for kids before games, or Pat Neshek.
When I took my daughter to Cardinals ST, Wainwright was signing for a crowd at which my daughter was at the end of. He must have signed for fifty people, at least. Just before he got to my daughter he said "Gotta go, guys." and took off. Some people who were next to us tried to call him back, saying "Adam, please sign for this little girl." but he just waved and kept running.
My daughter was a little disappointed but I told her to appreciate the fact that he signs at all, because he doesn't have to. He was the only cardinal player who had hung back to sign.
We went to the game after that practice and she got plenty of autographs and a couple balls tossed to her by players, so she did alright.
Active or retired, there's plenty of things these guys could be doing with their free time, so I'm grateful for those who sign, but I'm not going to criticize those who won't. I just wish those who know they aren't going to sign would hit an RTS on stuff so I could get my SASEs back.