said by swhitney2003 :

I think p2p has very little to do with the capping of mobile data plans. Users are probably using their phones more than ever to browse websites and watch media on their phones... something that their plan wasn't initially set up for (email use). The wireless carriers don't want their service to be used as if they are an ISP, since their network is not built to be that. I think this is more of a move to stop people from using their phones as an internet connection for a house... rather than because of p2p usage.