Back when I were a Lad!!........chucking bags and freight into 737's (no Magic Carpet) and 146's in the NT you would certainly know when you came across a 32 kg bag, heavy tag or not. A 32kg bag is bloody heavy! All the correct "bend ze knees" crap goes out the window when you are bent double in the hold and it's all back and arm strength to get the job done. You unload and load an aircraft manually in a 20 minute turnaround and I guarantee you crawl out of those holds absolutely f**ked. You do it all day and it's got to be doing some damage.
In the BMA's filling/unloading containers? Maybe it's different as the time and workspace constraints are different.
What I always found amusing was if a bag (or toolbox usually) went over the scales above 32kg, the punter would be told that it was too heavy (for the porters to lift) and would have to be broken down into two bags, or consigned as freight. Then they would pay the freight cost, a con note would be slapped on the side and I was now "allowed" to pick it up as it wasn't a "heavy bag" any more!