so I spoke to the travel coordinator at the camp, who spoke to the counselor with the group. the other girl thought she was playing a prank on my dd, and has apologized to my dd.
the travel program has the kids sign an agreement about appropriate behavior. if they violate the agreement they can be asked to leave the program. the young lady was given a stern lecture about appropriate behavior and was told that if she violates the agreement again she will be asked to leave the program.
and she will have to pay for anything of my dd's that is truly ruined -- not the stuff that can be washed, only the stuff that is destroyed.
I'm satisfied.