There's a few issues with such a thing.
* One-sidedness - if you're complaining about a non-GTP member, how will they be able to defend themselves?
* Evidence - it doesn't matter who you are, we're not just going to take your word that x is a dirty driver. You have the same burden of proof as you do for time trial times. Evidence needs to be provided.
* Flame wars - if you're complaining about a GTP member, it'll descend into a tit-for-tat waste of everyone's time that never ends.
* Lag - your evidence (if you can provide it) might show that they drove into you, but their evidence (if they can provide it) might show they were never even aware of you
* Subjectivity - oh, and then someone (probably a member of staff or a WRS steward) needs to judge who's done what based on the evidences provided if provided. We have enough of a job sorting out what goes on here, without policing the entire internet.
* More flame wars - and then we're in the wrong for someone depending on what we said. I know of at least one occasion of a member leaving after a public allegation of wrongdoing against another member that they thought we should have acted on because of who they were, but which didn't take into account the lack of proof or the possibility of inadvertant wrongdoing through lag - they were right because of what they'd seen and we were wrong for not doing anything...
At best, we'll do something about GTP_ members if you can provide evidence for allegations of wrongdoing, but you do it by PM to the staff and not in a public thread. Public accusations just result in problems and ill feeling.