I personally don't have a problem helping out financially with a "grant" but not if they don't do their bit. Not having any genetic responsibility I guess gives me a different view to those that do.
At least I have enough room on the front yard grass to store the car while waiting for enough money to refill it again..
and see it as a learning exercise for her, but in the mean time you still have to work out how to finance it in the first place. After the first tank full, it will become much less of a problem.
Servicing costs were easily solved "I just won't service it". Insurance was also just as easy "I am not stupid enough to go out and drive into someone, I want to be insured if someone hits ME!".