So unless I have permission from the owner of a copyrighted song, I do not have the right to "perform the copyrighted work publicly." So this means I cannot play a party, a park, or anywhere where there are people. That guy at the guitar store who picks up a guitar he's thinking about buying and busts out a riff from (insert your favorite metal band here) is technically breaking the law, because he's doing it in public.
And as stated explicitly, I cannot have a recording of me performing a copyrighted "work" up, even if noone makes any money from it. I simply never thought about the arrangements or transciptions being copyrighted as well. I guess I'll be pulling down the two songs I had put up - I am not sure who transcribed or arranged the versions I played, but since I heard them from professional recordings, I'd guess they're probably copyrighted. I'm not even sure how to check, since I'm only aware of the performer and composer credits for either.
They do, however getting published sheet music for many non top-40 bands is very hard. That's where I think the ban is wrong, if you have a published thing then sure, getting it for free can hurt the label (not so much the artist), but if there is no published one getting it for free is proably not harmful.