Its people like that that will wind up getting the area closed.
Definitely. Although it may be a hassle and you might feel like a "tattle-tale" - you should always report this kind of stuff. The rangers are way understaffed, and can't ever catch anyone unless we report it. It's the only way to:
1) Stop them from doing more damage (which means less work for the rangers having to fix it)
2) Teach these folks that what they are doing is not right, since they don't seem to be able (or want to) learn from posted rules.
3) Keep what areas we have left from being closed to everyone.
I have reported folks before. One time I gave them a chance to stop, thought they might stop, but when they continued, I called the ranger/campground host. Several rangers showed up, the folks got fined, and the nonsense stopped. These people had been riding an ATV with no helmets (not allowed) on paved campground roads (not allowed) and (worst thing to me) playing on their ATV in the woods around their campsite in a no-trail area, tearing it up.
My 4x4 club spends so much time maintaining trails in conjunction with the Forest Service, and we have seen so many people purposefully going off-trail, even breaking down fences, and we've had so much land closed to us, that I don't hesitate to report folks anymore for off-trail or other illegal activity.