I think you can use technology, sure. You just need to be aware of where suspicion can come from and head that off at the pass so to speak.
For instance, any time you use a phone you either A) Have to use an app that people are familiar with, or B) Have to use someone else's phone. Personally I would say use someone else's phone whenever possible as I feel there will always be a suspicion if you use your own device. Simply because it's not theirs and they probably don't entirely understand how phones work - to most people, a smart phone is basically a magic device that can do anything if you know how to program it. Kind of like computers. Most people don't really understand technology and they are frequently grossly mislead by the portrayal of technology in movies and television. Just ask some random people what hacking looks like.
I also think this is largely contextual. In my shows I have a bit of information written down but it makes sense. Why would I drag someone up on stage then have them take out their phone to write something down? It would make me look unprepared. No one questions why Derren Brown has people write things down on stage.
But at an impromptu, close up performance I can totally see where you're coming from. Though I, personally, don't have things written down at all in those situations - using someone else's phone or iPod or whatever for mind reading could be easily justified.
The danger is how easy it would be to forget the spectator's perspective and not account for the natural suspicion that can arise from introducing unfamiliar objects. As I said before, while they may know what an iPhone is - they probably also "know" (in some vague way) that there's apps that do crazy things and that people can hack a phone and program it to do even crazier things. The performer has to be aware of that and discount those possibilities in a subtle way before the spectator even thinks of them.
The HP Lovecraft of Bizarre Magic