I was there. I spent the night before in Sausalito, and we came from the north, reaching almost the middle before encountering the wall of people from the SF side.

It was damn scary. People continued to crush in from both directions, and the bridge swayed despite it not being particularly windy. People in midspan were yelling in both directions for people to turn around. The trampling deaths at the Who concert in Cincinnati were not yet forgotten.

Just when we felt in serious trouble, people finally got the hint that they weren't going to make it across, and they retreated.