Not realistic. If it's open-sourced I can go examine the code for sure, but it's not a good use of my time (and I can actually read code, but even if someone had the time but can't read code?). I also have no way of knowing if anyone else has looked at the code at all, and if they have, whether they're skilled enough to determine that the code is kosher. Again, if I struggle with that, how on earth is a non-technical-minded person even going to begin?

The second question I haven't seen asked here yet, is why we need everything to be social to start with? My social needs are covered by Facebook and Twitter, and I don't install their apps on my phone either.

Given those two things, if an app (any app!) requires access to my contacts I don't install it. Period.