As long as you're not driving like a maniac, and it's for a good cause... Anything that happens then is your responsibility. Just don't do it ALL the time.

A cousin of mine couldn't resist the urge to bring her Camaro out from it's slumber for a quick drive on a beautiful winter day a few years back... Caught a small stream of water going around a corner, spun, and totalled the car. Since there was no insurance on it, she took YEARS to finish making the payments on it.