The truth is, after being repeatedly asked to continue, users will reply "yes" regardless of what was asked... that's were the strategy fails in my opinion, if not for the part which excludes administrator priviliges while UAC is on. :)
The biggest problem with UAC is that it's all-or-nothing, with a ton of innocent actions triggering it as well. It would be half-way usable if there was a way to set a 'danger level' or something, but in its current way every fart will trigger a 'allow or deny' pop-up, which just trains the average user to always click 'allow' without even reading the messages anymore.