Arrest them and let them spend the night and next day in the unheated armory in DC with no beds, no food and only cold water in buckets.
This liberal bs of blocking traffic has to be stopped. It is dangerous for the law abiding citizens needing to drive or walk in the blocked areas.
Give anyone, who blocks traffic in a protest, 90 days hard jail time like cleaning up the streets they blocked, and big fines that even Follywooders will grimace at.
How do you expect them to be arrested when the MAYOR is there? This is not a complicated concept.