Answer: you have to bulldoze them. (But these are good libs just trying to get to work!) Too bad.
You know as well as I there are ways to do this. And I am PRECISELY getting around the "logistics" by having this be a mass individual movement as opposed to an "organizational movement." The goal is NOT to "show up and protest" (logistics). The goal is to so completely tie things up that the OPPOSITION must plan logistics.
Use your head. Help find a solution. You're sounding like a Tory in 1775 :)
DC is a three day trip for some, so getting stuck there without your car would be terrible, but having 10,000 or more people show up in every down town area of every major city, as individuals, and block traffic, and walk away......
If they returned to their cars within a few hours, they would have caused chaos, and made their point.
Just thinking out loud.