Similarly I would drive a group of youth somewhere and not ask for gas reimbursement. However, I would imagine gas reimbursement is easier to obtain than injury insurance help. That seems like a big hassle.
I have no problem donating above and beyond tithing and fast offerings for things like gas or copays for injuries. It doesn't really place an excessive financial burden on me, and it's for a great cause. I'm glad to help support it.
However, if it's a financial burden it could be totally appropriate to get reimbursed. My original response didn't convey that, and I'll edit it.