All this talk of mail carriers and deliveries brings back memories. Mom and Pop were both career USPS (Dad started as a carrier and later managed the mail trucks. Mom was in management). Sister and I did 90 day stints as carriers and clerks. Oh the joy! Now...this is a long time ago, but I do know that at one time the postal routes were actively timed. If the carried had a "walking" route, then he or she had exactly so many seconds between each house. That meant the carrier needed to cut across lawns to make the correct time. If they took too long on the street, it was frowned upon. If that happened too many times, there could be disciplinary action. (Also - if you, the home owner didn't like the carrier cutting across your lawn, you were required to file a complaint with the postmaster and the route time would be adjusted accordingly.)
Same for driven routes - x number of minutes to complete a "normal" delivery day.
That could be the reason that some of the carriers are hesitant to get out of their vehicles.
Or - they could just be contrary and don't want to

.
And yes...EVERY WINTER in Chicago, there are news stories with the Mayor and other public officials telling folks that they can't put their stuff in the street to hold their shoveled out spot. Every winter...no one pays attention. The lawn chairs go out on the first snow and usually stay out until the spring thaw.