If an error in judgment is made and the rules are broken (even inadvertently because 'intent' cannot be determined impartially) and a scorecard is signed, a DQ is the result. It's a player's responsibility to govern themselves by the rules. The nature of the game, no matter how an infraction is called to attention for a player, is of honor.
Therefore, I feel it was appropriate for Padraig Harrington to react with grace and acknowledge his error and agreement with the correct application of the rules. In the case of television, we all want to watch the best players compete. Not every player can be televised. It is the way it is.
Life's not fair, but golf has a rule book. Sure, add a rules official in the TV truck to monitor the broadcast and prevent an inadvertent DQ. Rules officials are out there anyway and do that on the course. It's in the best interest of us, the viewer, and to the business of the TV company broadcasting the event. But, bottom line, the player is solely responsible for his or her actions, and should face the consequences as written no matter how or when the infraction comes to light. Golf has and should always be self-governed.