what is the reason of adding a 6 edition of an event without any releases?

I think this is useful indeed. No releases doesn't mean that no work was done at the party, also this event happened then why should we ignore it ?

jok: We are 'documenting' ALL activities of the demoscene... if there were no releases at a party... so what?

Also, it's a "jumping off point" for someone who may know more. If nothing was found on someone's search, then they are less inclined to fill in blanks and make details or even releases available. Anyway, this party was not held yet, so that may play into the _no releases_ bit, thus far :P