I have never liked bootlegs - don't buy them, don't own them. I'm not really fond of legitimate re-issues - I'd rather have a CD compilation. However, I can't see how you have a problem - the release of bootlegs does not affect your collection and its value. Indeed, what does it matter how expensive your records are? Why are you DJing at events were people are carrying out such a reprehensible act (to you)? Indeed why are you DJing? take the records home and play them, I assure you, you will get pleasure listening to them there and no one will spoil it!
Mike