I have struggled with this idea. I can play bass, and I mean I can really play bass, but memory has never been on my side. I just can not internalise the amount of songs that others seem to be able to, I don't retain information like that. I can do it, but it takes me a lot more work than it seems to take my peers. I'm seriously looking at buying an iPad as a music stand and having it up on stage on gigs where I've had to learn a lot of stuff (structures are my weakness. I can keep up with everyone else's memory just fine if I have a few little notes about the structure).
I'm on the side of the stage anyway, I don't think anyone will really care if there's an iPad on a music stand (ideally in front of a monitor though). I just don't think anyone will except a few wet blankets at rock gigs. In fact I think it will help me get seriously a lot of work