A lot of cops carry a spare concealed at the back of the waist, to avoid a very embarrassing situation. Paramedics carry them, for the patients they may get from the cops. Crooks may carry them, for obvious reasons I suppose, and crooks do occasionally use cuffs. Then there are, ahem, recreational users of handcuffs. There is nothing illegal about having or carrying either cuffs or keys in most jurisdictions, but, yeah, it might buy you a lot closer scrutiny from the local gendarmes. But for the life of me, I can't think why I'd need one in my BOB.

Jeff