I have noticed there have been some mistakes, and I thought I read in a post somewhere that some freq's may also be outdated as well.
Also, I'm not sure, and maybe somebody in the know can correct me, but I believe the RRdatabase relies on the submissions of it's users, so, if this is the case, take some time and do a frequency search with your scanner,(one of the funnest parts of the hobby), also search the FCC database, ask around if you know any COPS or Firefighters, and submit the info to the Database, but please, I mean PLEASE try and make sure the info is as accurate as posible, nothing worse than taking the time to program worthless frequencies.
Good luck and have fun!