Actually watched them load my bag
 

One trip, flying CVG-TPA back in the day of the orange Priority tags, I sat at the right window watching them load luggage.

I actually saw my bag as the LAST ONE LOADED before they shut the cargo door.

Upon arrival in Tampa mine was one of the last to hit the claim belt.

My guess is they loaded it up on the luggage cart, but either forgot to bring it in or other carts filled first and mine came in last.

Either way Delta never did have that thing working.

I played dumb (not a stretch) and went to baggage asking "hey! what does this orange tag mean?". When the station manager explained about the "first off" attempt, I said he should explain it to the handlers since it was the last one on the belt. I think he got my drift. :D

In most domestic cases such as you describe last on MEANS first off.

I just flew PHX-ATL-SVO. In SVO, the priority tags didn't do anything. (For that matter, it took a long time for any bags to come out at all.) To be fair, there had been a last-minute change of equipment in ATL, so the baggage may have gotten scrambled when the unloaded the original plane and reloaded the new one.

For customs clearance in ATL on the way back, it didn't really matter. It took so long to clear passport control that the bags were probably circling for 20 minutes before I got to them.

In PHX, however, my bags were in the first few off.

Yellow priority tags are:
 

commonly know as "LAST BAG TAG" :D