"Fair Use. This is a doctrine which permits the reproduction of copyrighted material for a limited purpose of teaching, reviewing, literary criticism and the like. Without the fair use doctrine, books and movies could not be reviewed and colleges and high schools would not be able to study works by people like Arthur Miller. This is also how television programs such as The Daily Show are able to use copyrighted material in their commentary. "Fair use," however, is determined on a case-by-case basis. "
These bassless tracks are being used as teaching material, so the bass-playing public can learn how to play to them. Determined on a case-by-case basis? Get to work, lawyers.
"The Public Performance Right. This is the right to recite, play, dance, act or show the work at a public place or to transmit it to the public. Copyright infringement would occur here if someone decided to give performances of the musical "Oliver!" without obtaining permission from the owner."
I don't know about the rest of you, but I'm pretty sure I won't be playing to these tracks anywhere else besides my bedroom, to an audience of one - my dog.
I rest my case.