Maybe I'm missing something here, but what's the big deal. People around here have been pulling their cars & trucks off the road and randomly selling household goods, collectibles, & antiques for as long as I can remember. Nothing new around here.
Pros: No overhead, permits, sales tax, lease, fees, etc.
Cons: Nothing to get people to stop & shop except what you got showing.
Some people will spend a day and not make $20, others claim they make several hundred dollars a day or more.
Nothing more then being your own personal flea market. Just make sure you have a vehicle that holds a lot of stuff, & pull in a place where there is adequate parking and easy for people to get on & off the road.
Maybe the novelty is doing it in the BIG city! OOHHH! They're soooo trendy, those big city folk!