I never did carry them until I managed a sports bar/night club a few years back , in that time my health was much better and I did my part to help the security and bouncers out on occassion , so I started carrying a set of cuffs in my back pocket just in case ( the club itself was very nice , it was the not in the best part of town though and attracted a lot of , characters , shall we say) so I made sure I always had one key on me at all times. They have not left the place I put them since then.
(if you saw my key ring you'd know what a lazybutt I am in taking off keys I no longer need)
The thing weighs like 2 pounds.
Don't get me wrong though , I harbor no aspirations that I am going to ninja my way out of handcuffs while cuffed to an old steam pipe waiting to get my leg cut off by some psycho who had a bad childhood.