Aberdeen City Council have posted figures for the first day of enforcement, which started informally yesterday. The figure is down from the 1200 caught in an earlier test, and most motorists caught will be issued with a warning initially. This could be a good indication that people are already wary of entering the bus lanes, as well as the council doing quite a good job of publicising the roll-out.
There is an extensive FAQ which they have also posted about the scheme, which indicates that even at the warning stage, repeat offenders may be issued with a full penalty. They have also indicated that they will have mobile camera units designed to catch people in any blind spots that drivers may try to flout.