The official mahjong rules do not allow for "cross" bets by players on each other, or by outside parties on or against players.
Now this lady may have been playing by "house" rules in "her" games. But those rules do not apply to your table unless you all agree to them.
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Stand on soft 17
No mention of shoe emptying rules
Splitting up to 3 times (total of 4 hands)
Double down after splitting is allowed
Not explicitly mentioned but unlikely due to one card after split Ace
One card each after splitting an ace (and no resplit)
Ace and ten after split is 21
The dealer does check for ...
I have considered & re-considered the concept of involving a gambling aspect to the classic game of Risk. I have come to the conclusion that playing this classic game should not involve money as people whom like money games will gravitate towards poker & people who like strategy & balance of power will gravitate to Risk.
The best games of Risk ...