Does it keep your crabs in check? Reinforced gusset for those days spent dripping about food quality. Pocket for your comb as you like to play Freddie Mercury-slug balancer in your pants? Easy access back door for those crazy nights with the boys from heavy lift?
Im guessing its some sort of cottaging signal like hitchhiking, indicating that the signaller is free for all night in or a quick and torrid meeting behind the hangar. Must be taught at crabfat marshalling school??