You know how people joke about China, like secret police busting down someone's door because they're using a VPN to get on youtube? That doesn't happen. If there's one thing China gets right, it's not having police intimidate the people. No one is afraid of police here like they are in America. They are not automatically given respect just because they are police.
That said, Xinjiang is absolutely different. It's a police state. Remember that Simpsons Treehouse of Horror episode where Bart can read minds and the people are 'think happy thoughts, think happy thoughts'? That's what is going on in Xinjiang.
This van followed me for an entire day in one of the cities. When I arrived here, I tried to take a taxi. Taxis wouldn't stop, or if they did they didn't want to stop for too long or even haggle. When I went to the bus station, the guy behind the counter stepped away and called the police. I got a phone call not long after telling me to stay where I was. Police arrived and told me they know my name, my job, where I live in China, etc. We went to the police station where I got grilled on more questions and I was told I can't take the bus or taxi, but I could use a driver that they wanted for 450 kuai (a more fair price would be 300).
The next day I checked out of the hotel, and the concierge offered me a free taxi to the train station. When I told her my train left around midnight and that I'd rather walk around the city, she called the police on the phone and told them I wasn't taking the taxi and wanted to walk. I noticed this van following me after walking half a kilometer. Later when I walked to the old Muslim quarters of the city, two motorcycle cops (both Uyghur - lots of cops are Uyghur, btw) followed me and told me I couldn't take pictures at some places. When I walked to a village, some villagers saw me and we talked for all of 10 seconds until the van pulled up. When I started walking, I noticed the driver got out and went into their home and must have asked them what we talked about. I didn't talk to another Uyghur after that.
At the end of the day, when I saw the van waiting for me after exiting a museum, without looking them in the eye I told them to take me to the train station.
At the train station I met a young policeman who wanted to practice his English, spouting all the usual stuff ("it's for your safety" "you don't understand" etc). The most interesting thing by far is that he said the government forces the Uyghurs to celebrate Spring Festival.
I paid $100 to change my plane ticket to get back to Beijing two days earlier.
Here are some tanks I saw while leaving a train station. Sorry for potato quality but taking a picture of that would have landed me in trouble if caught. I have such a respect for photojournalists in countries who are not allowed to take pictures.
This screen is right next to the main square (and most important mosque in Xinjiang) in Kashgar. Big Xi sees all. Probably the worst thing I saw in Kashgar was just three Uyghur guys, looked to be in their early 20s, just walking and talking on the sidewalk, until a cop stopped them and asked for their ID cards. "Papers, please." Imagine dealing with that shit daily just because you were born the 'wrong' ethnicity.