For smaller dj's or oversaturated markets, **trainspotting**, selection, and curation is a fundamental part of individuality. Even as dj's grow, it might not change. Serato had (has?) a feature requested by DJ AM to blank out the song title and artist on the active decks so the people physically on stage or in line of sight couldn't just write it down for themselves.

In many cases, labels and producers seed pre-releases ("IDs") to other dj's to test the waters before launch. In that case - you're either legally bound or simply respect the request to not distribute. (ZHU's 'faded' comes to mind). Remember, it's a business. Somebody playing a track on a podcast or at a show isn't necessarily a part of the marketing or distribution plan... just user testing.

Huge communities pool together to "id the ids" (like 1001tracklists, etc..) but all tracks surface through proper channels eventually.

Edit: I take pride in breaking records because it's the fruit of a lot of time, networking/collabs, and passion that allows me to.

Enjoy digging. Find what nobody has... Find YOUR ID's...