The smarter thing to do is simply let the air out of their tires, at least two of them. I doubt seriously they have anyway of re-inflating the tires out in the boonies. And I mean that, actually taking the valvestem cover off and pushing in the stem so that the air runs out
Actually many people including myself carry pumps and patchkits on our quads.It would take several minutes but not too long to be under way.If you simply remove the oil fill plug and turn the quad on it's side,most of the oil will run out the fill hole in a very short time.I think that it would be pretty hard to miss the big oil patch on the ground.Then again you could unhook the line at the bottom of the fuel tank and drain the fuel from the tank.There are severalpossibilities that would slow down the tresspassers without damaging their property yourself.Some just slow them down longer than others.