We already covered the whole DJ/producer live or not thing in the Chems thread. It seems to come up a lot on here.
As someone who makes electronic music and performs it live, I always like to try and defend these acts.
I brought up the fact that Disclosure go out of their way to really make sure you realise they are actually doing stuff up there. They don't really need to do all this but I think they were worried about the exact comments we've seen in this thread. Each act is different and I've not seen an awful lot from Chems regarding this. Paul from Orbital has become more open to showing his setup, in recent years.
I like to term my live set as "Live Sequenced" because it is my tracks cut up in sequence (intro, middle & end usually but can have break downs and such too), some loop round until I move it on, some automatically follow on and I always transition from one track to the next.
The main things i'm doing "live" is messing with my bass synth's parameters (on some tracks) messing with the delay on vocals/bass/overall track, adding reverb to snare (in some tracks)and of course, triggering out of loops and transitioning into the next track (check out a recent video of me performing below) but I'm never actually playing an instrument live, it was all done at home or in the studio to make the track though.
I've just started practicing doing some stuff on the fly with my korg volca keys too.
It also takes a shit load of work in the studio to make this all work and quite a bit of practice so it's all good on the night.
The problem we face is people like Deadmau5 coming out and saying "anybody can do this" but people need to learn the difference between some of these acts and what they are actually doing up there.