The difference in skill is so important though. My best mate is into Aikido - some of the masters he's trained with wouldn't flinch if threatened with a gun. It's no threat to them.
There is the famous story of the Aikido founder who claimed to be able to dodge bullets - and did so, once dodging an entire firing squad. One of his students invited a game hunter to come and try hit him: the master accepted the challenge and stood opposite the hunter. Hunter stands there holding rifle, swings it up to shoot and the Master dives to the ground shouting "stop stop".
When they asked him why he'd given up he said:
"that man does not aim"
He'd met his match and bowed out.
The same lesson applies. The smart move may be to hand over the money - but if you assess the smarter move is to disarm him then you should do so.
Also; waiting for an attack or more stress is the worst thing to do. If you have the element of surprise it is a big advantage.
> Consider the thief's motivator is obviously money.
Often this is not the case - especially in South America. If your mugger has a gun your probably dead. A knife? Depends where you are.
> You only have to make a mistake once, or be a split second slow, to pay the ultimate price.
Again: if your confident and the odds stack up just go for it.
Disarming a knife holder is pretty easy and unless they are really good with it then your unlikely to get badly hurt if your on the offensive.