Yes I have heard of a few doing that. To me its just a huge surprise that in a game like this no consideration would be given to the need for voice chat to coordinate activities. The cross platform worlds are great but its seems like they stopped just short of the finish line
To be fair... do you REALLY want all that extra traffic on their servers?
The voice chat options for PS3 players are pretty limited. The best bet is if you have a smartphone or laptop you can use with a wireless or bluetooth headset. If you don't have a headset though, it IS possible to just listen using a laptop, which is better than nothing.