I really don't get why stuff like this is a no no. If that's the rule fine, but why does it have to be? I usually don't coach another player while they are playing because they didn't ask for the help. If they did, I'd help them assuming the rules allowed it. I have also been in tournaments before where I coached my opponent on a game and I ended up losing to that person on said game because of the information I gave them. Not a big deal. If the help wasn't asked for, I get it, but helping someone understand a game if they want the help, I don't care if it's mid ball, I don't see the issue with someone answering their question.
its like you're trying to keep pinball a secret so people don't get better than you.
Now if I'm in a close 7 game matchup with someone and they ask me for help, I might suddenly forget how to play, but I'm not gonna get all pissy if someone blurts out what shot they want to hit next.
If you ever get to the levels of tournaments where a rule like this would actually matter, it's still not needed as all those players literally know every game inside and out.