In previous incarnations of my rules for competitive doubles, I've talked about imagining that each pair has one bidding box to share between them. Obviously, you don't normally need two copies of each bid and the box comes with plenty green pass cards. There's a yellowish double card, an amber double card and several red double cards. Assuming no other penalty-triggering events have occurred, the double cards must be played in the order given. The first is for takeout. The second is two-way and/or cooperative. The third is penalty. [For more on the double rules, see DSIP rule summary and others.]
Obviously, this is just an illustrative scenario, not real life. But the idea of the third double being for penalty is a valid one. These days, I just call it the "three strikes" rule. Here's an example of it in use from a recent pairs game. With no-one vulnerable and in fourth seat, I picked up this hand: ♠ AJ7 ♥ AK3 ♦ 53 ♣ AQ654. RHO opened 1♦ and I had to choose an action. For better or worse, I made a takeout double (unusually, this was one of two occasions on which I doubled with 3-3 in the majors). LHO raised to 3♦ and it came back to me. I doubled again, this time cooperatively. Partner pulled to 3♠ and RHO bid 4♦. I doubled again. This time it was pure penalties. Yes, partner could have pulled with a very weak distributional hand. But he sat for it.
The result was down one – +100 for our side. This turned out to be the absolute par on the board though happily worth 60% of the matchpoints. As it happened, the final double made no difference to our matchpoint score. There were 19 total tricks on the deal, 10 for us in clubs, 9 for them in either red suit. We had a 10-card club fit and they had heart/diamond fits of 8 and 9 cards respectively. Of sixteen tables, all but four played a contract in our direction, six in their 4-3 spade fit and six in the 5-5 club fit.
It's quite satisfying when things work as they're supposed to. We were slightly lucky perhaps that 5♣ couldn't make against normal defense (they get two fast diamonds and eventually must come to a spade). Still, that's what you might reasonably expect with two balanced hands and 24 hcp. The bottom line is that each side did what it had to in order to reach the par result.
