Ok, you kinda answered your own question, yes they will complain...Is it a legitamate complaint, depends on what the complaint is, but it is more than likely legit.
And if I had a trail where only nice people played on it, yes, people still would complain, if it was on MY land They would not have a legitamate complaint, if it was on shared land (the greenie and I owned it) Then yes, his complaint would be legitamate as it's his area also and yes, he does have a say in what goes on. As I have a say in what goes on in the hiking community and yes, I complain about them too, they aren't perfect. Same with the motorcycles/atv's. But I have to say there are a lot of good things about each group that go on all the time, like trail repairs in ALL aspects of each sport.
It's unfortunate because my GF liked going out and exploring and wheeling, two times out to Reiter and she HATES the sport... It's amazing how easily people are turned off by the actions of others, and she's not one to be easily pushed into a train of thought like that. But you have to realize people are impressionable and they see what goes on up there, she knows of the clean-ups and such and what we (my group/croney's) does to help out to keep it clean and such. But people see what happens up there.... Usually the ones making noise are the bad ones.... so they get seen.