We were checking in at the CE desk at CPH last year. One of our bags was 25 kg and the other was 22. Mr. J remarked on how "light" my bag was but the clerk looked at me and mentioned that the other bag was 3 kg over and what was I going to do about it. I informed her that I I was pretty certain we actually got 32 kg. (Not my first rodeo.) She had to confirm this with her colleague and I mentioned that I read Flyer Talk every day. I don't know if she took the hint (that perhaps she should have a look here) though.
The bag in question was already tagged and sent through before she mentioned the weight, so I wonder how that would have been handled if it were overweight.