We were told that there was little crime, and indeed I never saw any evidence of street crime. I saw little graffiti. I never felt unsafe anywhere I went.
Occasionally we saw bars over apartment windows, as in the photo below. (Note also the leeks hanging out the window to dry. This was common.) In this picture, taken in Harbin, it looks like there is barbed wire below the windows, but I think those were clotheslines.
I did not see large numbers of police anywhere except Tiananmen Square. Airport security guards had "China Security" on their uniforms, which I was told was a private, not government, security agency. Airport security officers were courteous and professional. There were many China Security officers at the China Ag Trade Fair:
If you combine the previous post on poverty with this post on crime, one finds little evidence for the common Western notion that poverty inevitably breeds crime.