Upload & Sell: On
Yes, I'd be okay with it. Who cares? Are you really going to get referrals from a DJ page anyways, for that image? Come on now. You're just giving it to him to be nice, simple as that. So either be nice or don't, but ask yourself if this is just principle or does it really matter to you? And... how easy would it be for him to just Photoshop out your name and you may have never realized it, instead he is asking you politely.
I often send vendors images un-watermarked and some of them reply asking for watermarked versions. I'm happy to oblige if they want that, but I couldn't really care less either way. Makes no difference whatsoever to my business.