How many times have you seen it - the player slices his tee shot, and the ball rustles through the leaves on the corner of the hazard (yellow line). Because it is not possible from the tee to see 'around the corner and over the hill', we do not know whether the ball stayed in the hazard or made its way through to the cleared area on the hill (red line).
There still appears to be some confusion about hitting a provisional ball.
1. Can I hit a provisional ball from the tee?
2. Can I hit a ball from A (under Rule 26.1 water hazard) and call it a provisional ball just in case we walk up the hill and find my ball has made it through the trees?
Before any answer can be given, the definition of provisional ball is critical: "A 'provisional' ball is a ball played under Rule 27-2 for a ball that may be lost outside a water hazard or may be out of bounds."
1. If the player is certain that the ball is lost in the hazard, he cannot play a provisional ball from the tee. He must proceed under rule 26-1 "Relief for Ball in Water "Hazard.
2. There may be an outside chance the player's ball made it through the big trees and is "outside the water hazard". But the players will have to walk up the hill to search (see red line), in the forlorn hope it made it through! When it becomes obvious the ball is still in the hazard, the player has to walk back down the hill to point A (point of last crossing the margin of the hazard) and play a ball under Rule 26.1.
This is time consuming and the following group is right behind them, so to save some time, the player drops a ball at point A, calls it a provisional ball, hits it and then proceeds up the hill to check if his ball made it out.
The sentiment in so doing is admirable, but unfortunately, the "provisional ball" applies only to a ball lost outside a hazard or out of bounds. If he plays a ball from point A, this ball then becomes the ball in play (see Rule 20-4) as he has virtually declared that his ball is lost in the hazard.
After hitting the ball at A, he may still go forward and search the area for his tee shot, but if he finds it, it is too late to play it, as he has put another ball into play when he dropped at A. He has to grit his teeth, mutter something inappropriate under his breath and pick up the tee shot ball!
If he does hit the found tee shot claiming the "provisional ball" at A to be null and void, he has actually hit a wrong ball and Rule 15-3b becomes into effect (two stroke penalty or if fail to correct, disqualified!!) So have a look at 15-3b for the details!
Now a test.
Apply the same ruling to the 'power fade' into the hazard on Hole #4!!
Do I hit a provisional ball at B? Maybe my ball made it out to C!