To be fair, if huge numbers of people want to cross, it's actually mere politeness which keeps them from just doing it. If you just walk into a busy street, you

To be fair, if huge numbers of people want to cross, it's actually mere politeness which keeps them from just doing it. If you just walk into a busy street, you'd perhaps be hit by a car and injured or killed, but, if a hundred people do it the cars are forced to stop by the literal weight of the obstacles. I remember thinking about this on my way back from a London fireworks display (Richmond maybe? Somewhere that way) because obviously an entire crowd of thousands want to cross a street suddenly and they're not going to politely queue up and wait for light changes, they just all cross, because there's nothing car drivers can do about it. A few minutes away, with the crowds dispersed, it was necessary to actually use crossings, but outside the park where thousands of people had just watched the display a crossing was completely superfluous.