Based on an onsite news report, hundreds of delegates for Bernie Sanders organized a protest walking out on the Democratic National Convention last night in Philadelphia.

While most of the media focused on the official roll call nomination of Hillary Clinton, hundreds of delegates quietly used word of mouth, Facebook and other means to stage a walkout during the actual live roll call vote.

 
From the story:

The delegates protested outside the convention hall then staged a sit-in on the media area with police intervention:

The several hundred delegates stormed out of the convention hall before quietly sitting down and occupying the press tent, aware of how to maximize their leverage. Police surrounded the tent, and refused to let anyone in or out until the situation was resolved.

The renegade delegates explained how they pulled off the walkout protest:

One delegate, Dennis Slotnick described the moment saying, “I didn’t know it would happen when the roll call voting began.”