As much as I believe they are written for the sole benefit of the airline, the T&C's of your ticket outline the rules pertaining to weight....similar to what the previous poster wrote, when does this become dangerous??? Personally I'd like to see them weight the carryons as well. With the increased obesity in the USA and all the junk being carried onto the plane I do think that we're pushing the limit as to what "planning" the airlines do in regards to weight. I don't know the weight used per passenger, but i remember seeing it once or twice and thinking that it was not enough.

Want to pack extra weight into the carry-on pay the fee, or pay the fee to check an additional bag. This is the kind of stuff that results in stupid rule changes/procedures being instituted on ALL.