I was practicing on the MRT for event #2 and I got stuck a couple of times against a wall, or a tirebarrier. I couldn't get out because the MRT doesn't have a reverse gear. if this happens in the race because I get bumped, then it's race over....
Reset can be abused and policing its use can take a lot of time.
Say you give everyone who uses reset a drive through penalty. That allows someone who gets stuck on their roof to continue racing after doing the drive through (which will 'cost' about 20 seconds). However, if someone crashes their car but is able to continue to the pits to repair damage, they may decide to reset their car and perform the drive through penalty if they think the cost of the drive through penalty is less time than they would lose on the way back to the pits. It would also allow someone who has a puncture at turn 1 to reset their car, fix their puncture (and any damage) and bypass the long drive back to the pits. If you wanted to police its use (to stop the above 'cheating') it would take time for someone on the admin team to go through every race replay looking for people resetting their car and deciding if it was legal or not.
Sometimes you make a mistake that stops you racing and sometimes you get involved in someone else's accident through no fault of your own, but that's the tough luck of racing.
edit: P.S. I don't speak for the organisers of the Original LFS League.