How on earth can a DJ hope to break new tunes without the assistance of a mic to tell the audience what it is (even if it is covered )?....It's hard enough to break something these days even when sharing the title with the audeince....Oh I almost forgot, not too many DJs breaking new tunes these days .
Also how does a DJ dedicate requests?.....garner enthusiasm "Letsbee Avenue" ala Delia / Russ Vickers...."Taxi for Sharon"..."Please leave by the nearest exit, do not collect your record boxes", "the next DJ is"... etc....there are enough no mic venues on the club scene without this essential piece of kit being abandoned in soul clubs. I say keep the microphone plugged in - if people don't want to use it, or can't then they don't have to.