If people successful enough to get to the sim stage are looking to try and buddy up beforehand with their prospective sim partner via this forum then that can only be a good thing.
Getting to the sim stage means the job is there for you to lose. A couple of PM's and a meet up prior to the sim might make the difference between getting the job and not.
The worst idea in the world is knowing who your sim partner is on this forum and not doing anything about it.