What I find odd is the crosswalks here in DC where there's sign that says "Pedistrian MUST push button to cross." Yet it's not true. Actually, it is true at so

What I find odd is the crosswalks here in DC where there's sign that says "Pedistrian MUST push button to cross." Yet it's not true. Actually, it is true at some of them. If you don't press the walk button at some of them, the walk light doesn't turn on and the light is on red for a shorter period of time.