I've never been to Kunming, but I've lived in Shanghai for the last year and while a fair amount of people are riding without plates, it isn't really safe to do so.
I'm not interested in riding without plates, however I am wondering if it is a common thing to do as it would also likely show that license enforcement wasn't so common either.
There are some issues right now that leave me unable to obtain a Chinese drivers license, and at best I have my Canadian license. I'm not interested in driving cars, but I will likely need or be bringing a motorcycle.
Is it common to see motorcycles without plates? How safe would you feel riding a motorcycle without a Chinese license (but with plates)?
Do you ever see motorcycles/scooters getting pulled over? Or motorcycle police? Police traps? For anyone with motorcycles, do you ever get pulled over?