If he knew what she was thinking, maybe he could claim that seeming dense was some kind of defense mechanism, and the reason that people usually overlook him. But it's not exactly something he does on purpose, so that probably wouldn't be a great excuse.

"It's not just a rumor." Michael hasn't been home, he hasn't forgotten anything himself, but he knows people who have. And it was Rough. "I mean, I guess technically we can't prove that people who stay gone don't remember, but given what we do know, it seems like a pretty good guess. I'd say it's just the brain shielding itself from some kind of cognitive dissonance, like the whole alien abduction hypnosis theory? Actually, you might not know what that is. It's not important. Anyway, it happens to people who know about other worlds to begin with, so that's probably not it."