Maybe they didnt have insurance!!!
Back a few years, a friend got hit up the rear in his BMW. Young girl admitted it was her fault. Just a trace of a bolt head on the rear bumper of the new Beemer, he was going to let her go. Decided on getting her details, took it to the main dealers, crumple cans had gone. New bumper, new fixings, at a cost of nearly a thousand pounds!!!
Never think there is no damage.