I am new to the forum and new to tasting and trying out new whisky's (and needless to say hooked on this new hobby ;-) but are you really serious that opening a bottle doesn't hurt the value? I believe you have a contamination issue - you don't know if some guy took a slug and refilled with water or other blend unless this is for your own use. Leaving a bottle unopened, I would think, should yield greater value than one that had a cork was sniffed.
Plus opening the bottle and exposing it to "new air" I would think might also impart a slight difference as with wines and like bottles of scotch sitting on a pub shelf.

I'll admit I'm a newbie (somewhat) so please do correct and enlighten me further so that I too might learn from the those more experienced.
cheers
Bill