Yeah - i think it all depends on if it's billed as a 'live' set or not... if it is 'live', it should be your own work, but if billed as a DJ set or semi-live, doing the Surgeon thing and using other people's tracks and loops is all good (that's what dj'ing is :) )

As far as studio work goes - i'm completely against sampling techno to use in techno records... i don't have a problem with sampling a 70's funk or disco tune or something because you are still really creating something completely fresh, but sampling a techno tune to put in your own techno record is just cheating imo, and involves no skill or thought - practically stealing. if you get permission, you're effectively doing a remix which is another thing altogether.

machina