I think that's the key question. IME, it's typical for some priority bags to make it off first. Just not *all*.

Of course, the trick is to actually get the priority tag in the first place. In SFO recently, I wasn't given one because the bar-code baggage tag had priority written on it. Shockingly, when we landed in SEA, my bag failed to come out with the priority bags. In fact, it came out just a couple of bags shy of being dead last. On the other hand, I got the orange tag on the return trip, and it was the very first off the belt - got some great looks for that :-)