Very true, guys, and I agree that this must be what happened. I just thought it would've been fun, and another early, subtle indicator that all was not 'right' with Kirk.
This reminds me of when I was back in school. Every time we'd have a substitute teacher for a class, two random wiseguy kids would always decide to "switch identities" on the teacher. So, as 'Charlie' and 'Steve' would "be" each other, it was great fun for me as it never, EVER worked. Sooner or later, the teacher would call on, say, Charlie, and momentarily forgetting the clever prank, would just sit there as if he were deaf!