"Noooooo?" ....y-yeeesss, maybe? Which Tidus realises he actually is doing, and maybe that's not so cool to do with a pal, but. "I figure he'd know what an ID actually is! And he'd tell you!"

Tidus says it, like it's a reasonable result for (embarrassing himself) sharing this roleplay with Roland, and look, sometimes you just want to share the comedy of a situation with another individual than considering the effects of it on the other person?

Okay, so maybe he's being a big meanie right now.