People have been confused for decades about the real meaning of the crosswalk signals. The red hand doesn’t mean stop, it’s waving at you, telling you it’s safe to cross! The other signal is a chalk outline of a dead guy informing that you will perish if you try to cross.
I’ve always heard those crosswalk buttons don’t have anything to do with the traffic signals. Crosswalk buttons are installed because pushing a button will give a sense of control before you’re flattened by a city bus you didn’t see because you were too busy checking your twitter. There have been several occasions where people crossed in front of my car and told me to stop with their raised hand. I had no idea they had the right of way to cross a busy intersection while I had a green light. I finally get it, I’ve had these crosswalk signals mixed up all along!
If you visit a big metropolitan area you know it’s safe to cross when the city folk begin entering the intersection before the signal changes. Trust them.