The social contract in modern China is something like this:
We, the State, provide you, the Worker, with the privilege of the opportunity to make more money; we grant you economic liberties.In return, you, the Worker, agree to not seek other liberties, or to cause unrest which would perturb the equanimity of the State.
Chinese people, the Workers, have largely accepted and signed onto this social contract in modern China.
And, all good contracts need enforcement clauses.
The following are images that one sees if one dips off the tourist routes onto the locals' pathways, onto the traveller's routes.
Apart from troubled regions, where the social compact appears to be crumbling, or where parties feel that the other side's fulfillment of the bargain has not been maintained, these images are not intended as a show of force per se; they are intended as a reminder of the potential enforcement mechanism, should it be required.