Sven, I just read a fair amount of the thread you linked. One photo really jumped out:
In the first photo, I'm 99.99% sure the 9th tee is behind that clump of 4 small tree/bushes on the left side of the 1st fairway, going up towards the first green. This shows driving down the 1st fairway was a straight line towards the 9th green, especially for a left side pin. Just like the TW game shows, and other photos indicate as well.
The 1st fairway looks plenty wide for a drive off the 9th tee. The trees on the one side look sparse, and the bunker on the other side looks quite far off the line of play. In any case the bunker looks close enough to the 9th tee that it didn't come into play much.
If the creek was 300 yards out, very few players could reach it. Those who could would quickly learn in practice what club to hit off the tee. Getting to hit an 8 iron into the green, instead of a 5 or 6 iron, would make this a very tempting drive.
This does raise the question. With this seemingly big benefit, why didn't all the players in the Masters play down #1, all the time? Was it because of the golfers playing #1 themselves? Or was the drive riskier than it seems?