Having said that, over here, particularly with a cask strength whisky, one or two drops of water often opens the flavours out, which is really helpful for writing tasting notes!
The idea of whisky and soda water rather horrifies me though, but I suppose it is your Whiskey rather than our Whisky that is used for that? Or a blend, in which case we don't really care what anyone does with it!
Single malt is sacred though.
The drink which James Bond drinks the most in the books (although he is by no means a model drinker. Why shake that martini?) is actually a scotch and soda, often identified by brand. So, presumably whisky and and soda is accepted in some circles.