gnasher, on 2014-November-30, 17:05, said:
I always wonder why people do this. It's not required by the rules, and it's rather pointless given that you've just handed the opponents a piece of paper that contains the same information in rather more detail.
It used to be required by the regulations, and many people consider still consider it to be good practice.
It's far quicker for you to give a two second summary than for you to hand over convention cards to your opponents, for them to look at them (which involves putting on reading glasses in some cases), then get past the main focus of your convention card helpfully explaining that you play Stayman and transfers over a 1NT opening, to find out your basic methods are. In practice, few people read convention cards anyway.
gnasher, on 2014-November-30, 17:05, said:
And why should they want to know in advance what your two-bids are?
1. If you're playing something unusual, it gives them a chance to discuss their defence to it.
2. If you're playing something unusual, this facilitates the opponents gaining the same information as you already have about the inferences from your system.