After my observation the other day that the freeways have come into play as spots for protesting pedestrians to swarm, a reader pointed out this article saying the practice has been around awhile:

In 1966, USC was chosen over UCLA to go to the Rose Bowl, even though UCLA had a higher standing. Hundreds of angry UCLA students marched onto the the 405 freeway, blocking traffic for 3 hours. They halted a car bearing a USC sticker, pounded in the trunk and ripped wires out of the engine.

Another reader emailed that UC Santa Barbara students used to invade the freeway near Isla Vista. I'm with Chief Bratton on this. As he said when students ran on several freeways in 2006: "That's not free speech. That's insanity."