PAPA does not actively monitor all games, but they do have someone available to make rulings at all times, and they do have someone verifying that the scores submitted are the scores on the game. Also, while not actively monitoring every game, there are people around who are observing that for instance the person submitting their name is the one playing the game, that the person doesn't restart in the middle of an entry, etc. I would argue that Modern Pinball has this level of observation in place. Francesco is there at the booth when qualifying happens, he knows which players are in the middle of league entries, generally keeping an eye on things, and taking scores/making rulings as necessary.
This is different from a situation where the games are in a bar/restaurant with a bunch of employees who are not actively watching them, and whose main job is serving other customers. They can't make rulings, they have no real concept of how the league works or what the rules are, and their ability to maintain the accuracy of these entries is limited.
This all seems pretty common sense to me.