The Takeout Double for Penalty

Bridge is not a game of deceit. You don't win at bridge by misleading the opponents. You win at bridge by describing as accurately as possible what cards you have and then figuring out how to most effectively use those cards to take tricks or get to the best contract. Making a takeout double when your best suit is the one they just bid is very misleading unless you have the agreement that double is for penalty or the totally absurd agreement that the first double just shows a good hand and later doubles are penalty. Failing to raise partner when you have 6 card support is bad partnership bridge as is rebidding lousy 5 card suits rather than preferencing to partner's "first" suit with a small doubleton, winning with the higher of touching honors, and giving wrong count at almost any point in the hand when partner could potentially care, among many other things but those all come to mind from yesterday.

I saw a hand yesterday near the end of the Nickell-Wolfson semifinal match at the Rosenblum Cup on vugraph where Zia and Hamman let the opponents make a 3NT contract that had virtually no chance. It was board 30 of the final set and it was all because Hamman gave false count in clubs, which quite reasonably led Zia to believe declarer had no entry to dummy's long club suit, http://www.bridgebase.com/tools/handviewer.html?linurl=http://www.bridgebase.com/tools/vugraph_linfetch.php?id=15598 Zia wrongly cashed a high card in a side suit prematurely. That nearly cost them the match.
http://www.worldbridge.org/tourn/Philadelphia.10/Results.htm

Time and time again I see people, particularly random players in BBO, make this bid in which they first make a takeout double and then later in the same auction make a penalty double of the same suit. 1D-P-1H-X; 2D-P-2H-X; P-P-P. The doubler's hand: AJx, KQJT, Txx, QTx. The worst part is the doubler's partner "converted" to penalty with nothing in hearts and 4 good spades.
Later on, we had the auction: 1D-1S-X-2S; P-P-X-P; P. Again the doubler has spades (AQJxx) and partner opener "converts" with 2 little. How hard is it to understand that once you make a takeout double of a suit, further doubles by you in the same suit are also takeout, presumably with a little more values than you showed the first time?