FWIW at NRT on arrival from LHR our bags tagged with the orange priority tags as well as the white "first" tags stuck in the destination labels (an overzealous agent at MUC) were the first two on the carousel -- and gently placed upright by two attendants! (but that is a NRT thing!). At MUC having flown NRT-LHR-MUC our similarly tagged bags again were first off. So occasionally it works. At LHR my priority tagged bags have always been middle of the pack.