That sort of thing has to attended on the spot. If one has a feeling of trepidation due to drunken and disorderly behavior, excessive odds by number not in your favor and the like, then as Houndoc and OCNORB have stated, simply take note of the vehicle(s) License Tag/ make and model/ number of involved persons and beat a hasty retreat to the nearest authority who can effect action.
If you fail to act when obviously wanton and destructive (or even a totally *careless*) action is observed, the result will be to everyones detriment rather than those of the (ir)responsible party. Act now...don't wait.
Similar things occurred up in the SandFlats area back in '93 IIRC. People were breaking limbs off live trees to use either as fuelwood, or so they could park their rigs and motorhome/campers closer to their buddies. It got to a point where a certain Todd Campbell (an enviromentalist) went up there and put signs on trees - one very obvious one was right across from "Baby Lions Back" - on which was written something to the effect of "I am a living tree, please don't tear off my limbs or use for firewood".
As ridiculous as that might seem, the entire pattern of behavior witnessed up there achieved the paramount of absurdity. SandFlats became a completely regulated and pay for use area right after that. Cr@p still continues up there, but to a lesser degree - and now you must pay to be in it, and all vehicles are documented (or should be) when entering .
<sarcasm> Wonderful... </sarcasm> :-\
Capt. Picky