In his answer https://cooking.stackexchange.com/a/24354/6279 @user5561 indirectly makes the claim that it is 'preferable' to mix whiskey with water from the same source as the distillery.
So the answer is that yes, serious whiskey buffs would never mix "good" whiskey with anything except a little water (preferably from the same source the distillery gets their water from).
This is a claim I find intriguing and something I have never previously heard. Can anyone validate this? (or discredit it?)
note: I am skeptical because if there were truth to it I would think one would find branded bottled water in every liquor store.
[Edit/Clarification: When I ask for "validation" of this I am looking for more than just 'confirmation' of the claim, but some evidence or rational that explains why it is true. How does using 'the same water' augment the flavor, more so than 'plain' 'clean' water. What does the water used to create Highland Park do for Highland Park that it doesn't do for Jack Daniels? (and does the water need to be as old as the whiskey?)]