Conditional Comments – Spawn or Saviour?

Having found out IE10 will No Longer Support Conditional Comments, I wondered if version 1.3 of the W3’s Markup Validator supported them yet. Turns out it’s a no (surprise surprise)…

However: looking more closely at MSDN’s article on downlevel hidden / revealed comments (yes: buzzwords alert!) I notice that the Validator only complains about proper downlevel comments…