Well, good point. Any countermeasures to fake accounts buying things with stolen information would just make the game worse for everyone. So I suppose GS bounties would be out, then.
Well, one way to make it better is to limit who can participate. Both the bounty hunter and the victim must have reached a certain level in game. Make it a “Certified Bounty Hunter” achievement by tying it to achievement points gained, ships unlocked, battles played, things like that. That way you don’t get fake accounts participating in the system.
Of course now you still have to worry about stolen/phished account credentials, the second big issue in these things.
tl;dr: it’s not impossible, but people will always try their hardest exploiting any system involving real money, so this would have to be very carefully designed.