I understand rogolf that you are technically corrrct
But I'm with OB that if you make the call on the tee that the ball could be lost outside a hazard it is virtually impossible to then change your assessment when you get down where you think the balk was to say you are virtually certain it is in the hazard
If it could be anywhere else but the hazard off the tee then it's a chance to be anywhere else when you get closer to it IMO
Not saying the rules don't allow it - I just don't see it working in practice
Take a practical example.
From the tee you have to drive over a rise, behind which, is a ditch at or about your driving distance. You don't know the nature of the ground surrounding the ditch but last time you played there it was long grass beyond and in front of the WH.
You hit the ball straight down the fairway but slightly miscue. You reckon your ball could well be in the long grass short of the WH so declare a provisional as per rule 27-2.
When you get over the rise you see that all the long grass has been mown down to fairway length.
You and your group approach the WH and look all around. There is no sign of the ball on the fairway before or beyond the WH and it is so wide, there is nowhere it can be hiding in the light rough to the distant sides.
You can now claim to have KVC that it is in the WH.