Sony's already taken a pretty big shot at the used game market with the download-only PSP Go, and it looks like it might now be going some way towards taking physical media out of the equation as well. In what's described as a "trial run," Sony has added a new authentication measure to SOCOM: U.S. Navy SEALs Fireteam Bravo 3 for the PSP that will require gamers to first register their game on PSN before they play online. Once that's done, you won't be able to use the UMD on another PSN account, and anyone buying a used copy of the game will have to shell out $20 for an additional voucher to play online. According to Sony, that's being done primarily to combat piracy, but there's no getting around the fact that it also makes used copies of the game a whole lot less attractive to potential buyers. No word on any future games that will employ similar measures, though we wouldn't count on Sony giving up on this one too quickly.