From what's been said on this forum, primarily what you need to be able to do is prove legitimate ownership, that makes sense. The 'right to public performance' thing, whatever venue needs to be licensed for that, right? -- in order for royalties to be paid to the appropriate organization. However, also from what's been said, it seems like MP3s and the like are singled out as being illegal in general, where the concept of a "legal, purchased MP3" is not considered.and what if you have downloaded a legal MP3, can you play that out without any problems?
it seems it's time for a global (or at least european) law on how to handle this kind of thing
But the fact of the matter is that anyone who distributes for sale in an MP3 format wants (or doesn't want) their music played by DJs just as much as if it were on CD, vinyl, whatever, isn't that so? Then it seems like it shouldn't matter what the format, or whether the record store was "brick and mortar" or "cyber": just that being able to provide legitimate proof of purchase is the issue (so your download receipt from mp3tunes.com or itunes etc with resultant account debit) in the case of a legalistic encounter.
It should *NOT* that you have some stamp-act type thing issued only to the music providers that have somehow lobbied the proper government officials while everyone wasn't looking.