While Zack might have overlooked Demyx's approach, Squall hadn't - true, the guy looked like a native of the place, but that didn't neccesarily mean he was one. After all, there were blonds that weren't natives in the city - Cloud proved that much at least. But at least his arrival had kept him from answering the question at hand.

If he was lucky, the new person would even manage to keep Zack occupied long enough the let him have some time that didn't involve answering questions or straining his not-that-great social skills even further - especially if the guy was one of Zack's friends.

Besides, it would give him some more time to start figuring this new guy out - at least as to whether or not he was a threat.