Little known fact: there are actually very few LFS servers where deliberately causing crashes is tolerated. You might get away with it for a while on an unmoderated server, but it won't last forever. Someone will report you, or in some cases, a remote monitor will expose your activities, and an admin will serve you with a ban at a later date. They tend to be a lot longer than the 12 hour vote-bans you might otherwise be get too.

If you like crashing, either find a crash/demolition/stunt server, or stick to wrecking AIs in single player mode.