It's a hunch... not based on much... that the songs we see on YouTube are not paid for, i.e., no licensing has been paid, no monies passed on to the musicians, writers and publishing right holders of the tunes.  I think that's true and speaks very well of the Guitar Tricks site and their expressed intent.

As for song requests... I'm finishing up my fourteenth year here and I know of no requests that have ever been turned into lessons.  There might be some, but I wouldn't put any money on it.  😏  Some years ago there was a Song Request sub-forum.  As I remember, it was huge with pages of requests.  I believe that members' growing realization that requests were not acted upon eventually resulted in the elimination of the sub-forum and all that was posted there, three or four or more years ago.  I think it's all gone... I know of no way to retrieve those member posts, my own included.  Now, song requests by members are not visible, i.e., whatever is requested is not seen/known by other members.

At least, that's the way I remember it and I think the way things are today.  It is what it is - yada, yada, yada.  It is GT's site to make of it what GT wants from its business plan.  Members suggest - at its own risk, GT responds as a business in a way which may or may not accommodate subscribers. 

Frankly, I'm pleased with the instructors and the interaction I get from Admin.  I'm a little disappointed in my fellow members who complain there are 'no good songs', oblivious to the tastes and likes of others (they feel left out? try being an ageing boomer and dealing with GT's catalog  😂).  I don't think much of the 'I'm taking my ball and bat and going home' attitude that is expressed so much on the Forum but I also realize that's the only way members can vent.  Still, the complaints tend to the extreme, in my eyes.  Recently, there was a complaint that there were only two versions of a song to choose from; 'one is too hard, one is too easy.'  Lord help us if we descend into Goldilocks polemics.  😬

YMMV.

john