Our 13-year old was one of the kids in the Bridge 4 Youth program put together by a bunch of Seattle bridge players. This was a week-long camp, and was followed on Saturday by a club game. Bridge-playing parents and grandparents were encouraged to play, and so we played as a partnership.
Playing with my 13-year old, I was South on this deal:
Fast forward two weeks, and I'm playing in the Open Pairs in the local sectional with an occasional partner. The field is quite strong, and we are playing 2 boards per round. The opponents had just bid, and made, 6NT off us when I picked up this hand:
I opened my hand with 2C and got 2H from partner. I wasn't completely sure what I was playing with this partner, but I thought 2H was a bust hand, so I alerted it as that, and bid 2NT. Now, partner bid 3H. This is, of course, a transfer, but I wasn't completely sure what system of responses we were playing, What if partner really had hearts and had forgotten? I decided to give him a chance by bidding 4H. Wrong move -- partner, it turns out, wasn't sure what 2NT was -- he mistakenly thought my 2NT showed hearts (actually, 2NT by him would have shown hearts, and my 2NT was natural). So, he passed my 4H bid and essentially conceded 5 down when he couldn't arrange a diamond ruff in his hand or cash the queen of spades.
2C hands are too rare to have different agreements with different partners. 2D negative or waiting, it is, from now on.