The priority tag on my last checked bag sure didn't mean much when they were deciding which bags to put on my IAD-AMS flight...About 20 of us didn't get our bags. Most of them had had late connections at IAD, but I had a 3.5 hour layover.

Luck of the draw, I guess.

FWIW, during the past few years I haven't noticed that my bags come out particularly early as a result of the tags. However, Singapore and London seem to be pretty consistent about offloading the priority bags early.