I would say foreign teachers or Chinese ones also should avoid having relationships, sexual or otherwise with students in the same department as them at universities, for foreigners in China that usually means the English department. For an FT to have a relationship with an older post-graduate student or a fourth year student, well that is normal and healthy I feel. Many teachers have love affairs with students at their universities. I mean, we can't help who we fall in love with sometimes, right?

I think most people would agree though that ones own students should be off limits, and for me anyway I don't put myself in temptations way, I mean by not inviting my own students to my apartment. Only post-grad girls or third or fourth year girls from another department. You point about other FT's students is irrelevant in that context.