I had another mate have his bass head stolen from his car this weekend too.
And though it's heartbreaking and unfair, if you don't leave your gear in your car, it doesn't happen.

His head was stolen from the driveway at his house(inside the gate,I believe). And though I know how tedious and difficult it can be to offload your gear after a show, the proximity of driveway to house, to me, means that it's worth the extra effort every single time