First, the hog should not have followed you back there, since it was off course. That hog's gunner should not have fired since it would be considered chasing kills. I would more blame the driver for setting up the gunner for kills, even though the gunner shouldn't have shot. It's usually only the more experienced players that pay attention to where the hog is actually going and what it's doing, and know to stop shooting when the driver is no longer "racing". Even the experienced players will take a second or two to realize "hey, we're stopped" or whatever the driver is doing wrong.
The gunner of the driver who chased you was just looking for targets. If they were newer, they might not have known (or cared, I'll say it) that it was not a legal kill. But no, they should not have fired while the driver was not racing.
Second, I think there is a PR_ clan that is not related to BFM, and some people might put it on their name because they see someone else with it, just like they might do with other clan tags they see. You're free to report the behavior of anyone you race with. People with PR tags are no different than you and we have the same expectations of them that we have of you (and other guests in the servers). Someone with PR_ tags might have applied for recruitment with BFM, but they aren't held to higher standards nor do they have any special privileges in the servers.
If you'd rather not start a thread in the Problem Players board for someone, you can send a PM to an officer (an officer is anyone ranked Captain or higher) and we'll take a look at it, make appropriate notes where it would be... appropriate.
Thanks Meteor, you rock.