When I go climbing in the forest I do not "hide" from others. I do, however, have a rather serious attitude about wilderness ethics, meaning that I am going to be as quiet and unobtrusive as possible. When I clothe myself in earth-toned clothing it is not because I am trying to camouflage myself, it is because I am trying to blend into the environment, rather than stand out from the environment. When I climb quietly, it is not because I am trying to avoid attention, but because I value the solitude and silence of the forest. When I pull my rope up into the tree behind me, it is not because I am hiding it, it is because a rope hanging from a tree might seem offensive to other wilderness seekers who would rather not be held captive to signs of civilization in an otherwise pristine wilderness setting. When I leave the trail and walk to a point out of sight of other wilderness visitors, it is not that I am hiding from them, but rather that I prefer to enjoy the wilderness experience by myself. When in search of solitude, other visitors can be as offensive to me as I to them. It's not about hiding, it's about wilderness ethics and wilderness etiquette.
Now. Having said that, I will admit that employment of a good standard of wilderness ethics is also conducive to avoiding run-ins with those who might take offense over my climbing in the trees. You might notice that the same people who are getting busted by Authority are the same people who seem to be lacking in a strong idea of what wilderness ethics is all about. One of the main cornerstones of a good wilderness ethic is the idea that visitors to the forest should blend into the environment rather than stand out from the environment. The climber who goes off into the forest wearing a bright orange tee shirt with a rope, harness, and bigshot hanging over his shoulder is not blending into the environment; he or she is standing out from the environment, asking for attention. When you climb a tree right next to a trail you are keeping other forest visitors, as well as yourself, from enjoying the solitude, and you are once again standing out from the environment. When you go into the forest as a group, there is usually much talking and as the climb is begun there is usually much shouting back and forth between those in the tree and those on the ground. This is offensive to other visitors who have come for the beauty and solitude, and once again these climbers are making themselves stand out from the environment.
If you like to climb in groups, talk, make noise, wear bright colors, and show off the fact that you are a climber, then you might do better to climb in places where such behavior is accepted. If you are going to climb in wilderness then you need to adopt a strong wilderness ethic, or get used to the idea of being seen as an unwelcome guest. I, for one, have never been busted by a ranger or any other authority and I climb fairly regularly just about anywhere I want to climb.
Just the other day a ranger friend of mine told me that he knew I had been climbing in his area, but because I stayed out of sight and went about my climbing quietly, without attracting attention to myself, he wasn't going to tell me not to climb. In fact, he wants to go climbing with me. He says that there is no rule against climbing trees in his area and that he will not make a rule unless climbers themselves cause him to have to make such a rule.