Hello, Elle!
Now, firstly I am no expert on the Rules of Golf!
And to complicate matters the US PGA altered some of the rules recently, and I know one is about leaving the pin in the hole when playing towards it, but little else.
But, I do not know if Rickie had the option to have another shot to the green, rather than take a drop from the water hazard.
Sorry!
I am very dependent on the commentators keeping me right on things like that.
And I do not know why on earth he was penalised for his placed ball rolling into the water, although the rules official deemed it to be "in play" and I can understand and agree with that.
I'll maybe try and find out a bit more about it.
The Rules of Golf are not particularly well known to the players either.
There was a famous incident years ago involving Craig Stadler and a bush!
Craig had hit his ball under a bush and the only way he could play it was by going on his knees and swinging at it.
But the ground was a bit muddy so the bold Craig spread his towel on the ground to keep his trousers clean, and hit the ball up the fairway.
All fine....but no!
A televiewer phoned the course and said Craig should be penalised a stroke for "improving his stance", and he was!
Not sure if it cost him the tournament or not.