There is far more social unrest and dissent here than people at home realise. It usualy relates to compulsory land clearances by the government with locals arming themselves, attacking police / gov't officials, and sometimes winning. This is never, ever shown on tv though.
Occasionally a factory will be sold to private owners by a local authority and the workers will revolt, often taking (government officials) hostages, occasionally killing them.
Beijing keeps a tight hold on all things within the city, but further afield it's more opaque, with cities and counties often disregarding government edicts if it suits them (ie there is money to be made)