Actually that mp3 I'm guessing is on an open source liscence... meaning it can be put ANYWHERE without copyright issues. The file name looks like he got it from archive.org which only has open source music. UM along with lots of other jam bands, feels live music should be shared freely, so recordings of their concerts are legal to own and distribute freely.

... though I can't say much about all the other copyrighted stuff that gets posted.