Just my two cents on this...
There are Rondevous..and then there are rondevous...
I guess a lot depends on who is having the voo, what the parameters are for those who wish to attend, and so forth. One thing I do know, this thing with rock candy and all that...imo, those are more of an outing than a voo. Now, don't get me wrong....on the opposite side of the coin one has those juried events...to me, those are something I avoid, but, I also don't really get much out of going to a voo where almost anything goes as far as being historically accurate. Now, I guess I am being a bit fussy here over one item I really cannot understand why/how most voos permit it. That is where one sees people in revolutionary garb as well as having the fairer sex show up in fairly fancy dresses. Now come on...no way is that "period correct" imo. For one, I don't ever recall hearing of any white woman making it to a rondevous until about 1836 or 1838, and those were missionary people.
Anyhow...getting back to names...most folks I know who have a "handle" got it from someone who gave it to them, and, as was said..not entirely complementary. That....is part of the fun of it. I guess from what I have heard, there may be instances where some nick name is a bit hokey, especially if the owner of it picked it up himself. Did the mountain men have nick names? I dunno..My guess is some did, some didn't. The thing to remember here is...way back then...a man's business was his own business...one just did not pry into it or ask to many questions. So...he might come up with a name out of the blue, so to speak. Didn't make any difference to those folks back then...you called him by the name he told you.