Interestingly enough, the version of Mao that I learned doesn't play this way.

Variations of my familiarity:

  • Talking is allowed, but not asking questions. This is likely because 1. When talking to each other, people are more likely to slip up and ask questions, 2. The game is a little too serious when you can't joke, and 3. It's easier to pull other people into the game if they ask 'what's that you're playing' and you can penalize them for asking a question, and then again for not saying "Mao"...
  • All rules must involve a verbal cue. This prevents people from having the rule involve, say, blinking their right eyelid, or something else incredibly stupid and nigh unobservable. However, the result of the verbal cue can be, as above, penalty cards, skipping other players, etc. See the Do you want to buy a duck?1 rule...
  • No penalties are applied during Point of Order, aside from looking at cards before Mao says "cards up", but the Mao controls what is discussed during one.
  • Penalty cards may not be played during the turn incurred. This keeps people with a bad hand from asking stupid questions until they get the card that they need. I have done this, to my eternal shame.
  • If the series rule is incurred (during which, you could play a 2, a 3, a 4, etc. of whatever suit) only the first and last card of the series are named. This rule was created because there was a game where face cards counted as draw fours (thus four penalty cards per card named) and as long as players could keep laying them down, the sum kept climbing until it reached a player who could not add anymore cards to the pile. Thus the aforementioned player who had to draw 96 penalty cards in one turn, and why I generally play with 3 decks at once.

That's all that comes to mind off hand, without going into the actual rules themselves.

1. See the rule by Squalor under this link to see how this works, and assume a penalty card for each step missed by anybody. Natch.