Having the man who's been stalking you for years finally come at you when you're at work weilding a chainsaw is scary enough. What's scarier? When he only has one arm.
Maybe you wouldn't think a one arm man weilding a chainsaw is more dangerous than a man with two arms doing the same. Think about it though: there's less opporunity to restrain a one armed man. You can't twist the other arm to help make him drop his weapon.
Then there's the additional headache of trying to cuff a one armed man. You'd better have something you can cuff him to, or have one of those restraining belts you can attach the handcuffs to. I suppose you could take a whole bunch of those zip ties and make a belt out of loops of them that you could then zip tie his one hand to.
If you ever wondered about the things that go through my mind when the music's playing...now you know. Thankfully, for the friend of mine whose one-armed stalker accosted her at work, well, he's dead now. Karma took care of him by way of a car accident the day after he got out of jail, which ironically is how he lost the arm in the first place.