I mean... He could just be played by a newbie? Or he's just really nice. The way I see it is why would someone roleclaim cop if they weren't? To get people to believe they knew who was scum without being pegged as scum themselves. But Zhao was scum. It would be a stupid this to joke about, espically if it came to surface that you were not a cop. So if you thought someone was joking about roleclaiming cop wouldn't you also be suspicious about said person, unless you also wanted other to NOT be suspisious? That's just how I see it.