How good does it have to be?

Some Other Time | Blithe Spirits | Kempt:

"The Magnificent Bastard recently devoted a post to the question, “how good does a scotch have to be before you won’t use it in a Rob Roy?.” Understandably, it led us to pose the following counter-query: “Does anyone still drink Rob Roys?”"

So, FAU has now become the "Scotch Master of the Interwebs" and how good does the scotch have to be to avoid mixing it?

Ironic post after my "rethinking drinking" post below.