How many people? The more people you put (let's say fixing a pothole) the safer it is. Would you put 1 extra? 10? 100? 1000? At what point do you stop?

There's absolutely a limit where adding another person only adds marginal safety. For instance, children who don't know they should not jump to jump a barrier and then go into a pothole should not be allowed alone on the streets. We are not talking about a random hole in the street, these things are already heavily warded in Japan with barriers and signs AND on top of it there's also workers AND on top of it the mentioned security guards. My argument is, many or all of these security guards are not needed.