I disageee that Turnoi is right. Often he is not right, he has not lived in China for a long time. Living on campus is OK if you have a decent apartment and you can invite anyone to your apartment whenever you like. At my former university I came home drunk many times, even brought young women home to my apartment sometimes, nobody ever said or did anything about it. One of the Philippines teachers was living with her boyfriend there, another FT was living there with his Chinese girlfriend. And there was a police station next door, but I never saw any police ever come into the uni. I agree that an FT should never become romantically involved with his own female students, and if you bring girls back to your place for the night it is better if they are not from your own university, and also better if they are women over 25 or so.

I invite people to my apartment all the time also, nobody cares who I invite there. The place is "guarded" ( sort of ) from Monday-Friday 7am to 5pm, after 5pm there is no security, on weekends there is none at all. Turnoi seems to think that a curfew at a uni will stop a student from having a sexual encounter with a teacher ( FT or otherwise )
Most girls dormotories are not locked until 10.30pm, plenty of time between about 6.30pm and 10pm for a pretty young Chinese student and an FT to have an erotic encounter.

As for the gate staff, I never had any problem with them, they never took much interest in me. But of course, if you are an FT with a young Chinese girlfriend from your own campus you should not hold hands with her inside the uni grounds or put your arm around her or kiss her in public. Yes, people will talk. Physical contact is better left for when you are inside your apartment. You must be discreet. Some universities have no policy in regard to student-teacher relationships. The uni I was employed at in 2008 had no such policy. However,like another poster said, the Chinese love to gossip, if I had a Chinese girlfriend at my own uni( a teacher or student ), I would prefer if nobody else knew about it,it is called privacy.