[Girchuck]

The turn bet with AK against a single opponent is often done for free showdown unimproved. If check-raised, you fold confidently
If you cannot confidently fold to a check-raise with AK unimproved, this is not a good thing, because you will be more often check-raised with a pair and lose your free card privileges and your free showdown. AK unimproved is a drawing hand more often than it is the best hand