Blocking busy downtown sidewalks is rude and disrespectful of others no matter who's doing it or for what reason unless the blockers have a special permit. 

Perhaps we could find and power up some disabled seniors that share in our dislike of having rude people block our downtown sidewalks and would like to take action. Seniors with the big, wide and heavy electric powered wheelchairs. They could fly their handicap permits and beep a small horn to warn people that they need through. Think of them as "senior sidewalk sweepers" doing their civic duty.

It maybe legal to loiter sprawled across a sidewalk, but, to my knowledge, it's not legal to deny a handicapped person public access, especially on a downtown sidewalk.