If that is the rule you use, then I say if you can use it to your advantage, so be it.
I recall the controversy that Ernie Els had with his first U.S. Open win.
He hit a tee shot way to the right with no chance of reaching the green, but because of the line of sight rule tournaments use on the tour for man made obstructions like a grandstand, Els was able to drop his ball in such a place that he had a clear shot to the green.
He got a par on the hole and won by one shot. Had that grandstand not been there, he most likely would have had a 5 or maybe a 6. In this case, he hit a very bad shot and was able to use the rules to extradite himself.
The same goes for your 12 rule. I would even go so far as to say, had your partner continued on and got a 13 on the hole, he is still entitled to put a 12 on his card as the official score and in fact if he put down a 13 and signed it as such he would be disqualified for signing an incorrect score card.
Rules is rules and you have to live or die with them. Sometimes they help you and sometimes they don't.
That is my take on it.
Regards,
Kent