They can't *make* her go, but it will be beneficial to her if she does go.
My child got really upset at the thought of going on camp, and I was adamant that he wasn't going. We'd have tears and temper tantrums, saying how he really didn't want to go and would miss us. I felt awful, but in the end (and after speaking with his teacher) I put my foot down and just said he was going and told him he'd enjoy it.
That sounds a bit mean, but I'm really glad I did it.
He had such a great time and, out of all the class, only two didn't go. They were then singled out when the rest of the class got back, which my son would have been had I allowed him to not go.
It did wonders for his confidence. I never imagined that just 5 days away from home would change him so much.
He went away a shy, reserved and slightly nervous child, and came back kevin the teenager! Lol
He used to hang around with two or three friends, but came back from camp with a bigger group of mates, and a lot more confidence to mix with other kids.
I worried like mad for the whole 5 days, and couldn't wait to have him home, but hearing him talk about it for the next month or so made me realise I had made the right decision and would do so again without any hesitation.