Face it, Beatles music is part of our global (western anyway) culture, and using the Beatles catalog as a starting point/testing the waters for DRM-free would be pretty low risk.
There could be a problem, though. I will be surprised if the Beatles sell very well, with or without DRM - the real fans already have their music, and a LOT of younger folks don't even know who they are (seriously). If the Beatles become the test case for DRM-free music, I can see the music companies saying "See, we did exactly what Steve Jobs asked for... and we're not getting anything out of it! Sales are still low. BTW we're suing an 11-year-old autistic child for copyright infringement this week."