I think the event coordinators should set the requirements, though I can't say much since I've taken sub-par vehicles places that they should not have been. Still I have also parked my rigs and hopped in with a friend when I realize that I'm in way over my head. It all boils down to thinking of others and not hold things up just because you wanna play too. Three things come into play when determining your capabilities, first how experienced of a wheeler you are, the limits of your vehicle and if you get into trouble you should have a group that you are with and that are willing to get you out of the way of others. It pisses people off to have to sit and wait for hours for some novice wheeler that came alone and has a relatively stock vehicle.