This is a double-edged sword either way you look at it. If you're on a dead server, but farming constantly and posting to AH then you will hit the auction post trigger and get investigated or continuously get undercut then have no players to C.O.D. mail. If you're on a popular server then anyone who has botted for at least ten minutes understands the pros/cons already which combined realms really change that much due to this patch.
Seems like Blizzard is only reaching out to people who have their own interpretation of this feature made up in their mind when all it really does is find more botters easier, flag them, and give them the boot quicker. The trading aspect will be interesting. If you can send mail or trade without the auction house from a low population server to a medium, high, full, or locked then it might help out botters.