Interestingly enough, back when I was in the Florida Joint Task Group we would borrow a UPS truck and one of our DEA agents would get into uniform and drive the vehicle to deliver narcotics on a "controlled delivery". It never happened during my time, but I always wondered what mayhem would ensue if a couple of goblins tried to commandeer the truck while our guy was aboard and numerous agents and the locals assigned to the task force were surveilling it.
(Had something like that happen with a couple of young fellas in a precarious section of Brooklyn where our surveillance van was made up to look like one from the phone company. My partner and I saw the two guys approaching with the intent of opening the rear van doors to rip off whatever gear wasn't bolted down, and were extremely surprised to find a couple of surly dudes with guns pointed at them for their efforts once they opened them. We just told 'em to go and sin no more as we had bigger fish to fry that day.)