Choosing to question authority has proved an even more dangerous thing to do for many of these individuals that have lost their lives in these type of scenarios. I get it though, you are talking about a different type of danger - and to be honest I probably agree with you on the social danger of not questioning authority...when appropriate.
A lot of people have died at the hands of police, irrespective of whether authority was challenged or not. "Challenging authority" is not the main issue here.
The bottom line is that most of us all live in a society where police officers are given the authority to question and arrest people for various things. This isn't an inherent authority, it is an authority given to them within the structure of our societies. The court system typically takes it from there - but that is entirely a different conversation. There is no question in my mind that there are asshole cops that question people for no reason and are overly aggressive. I will even agree that there are people that are stopped and questioned for no reason at all - although I would guess that this is an extremely small percentage.
Where do you live? In New York City, Stop and Frisk was a program targeted at black and hispanic communities, that resulted in the illegal search and arrests of thousands of urban folk. This was not done by an extremely small, negligible, insignificant, infinitesimal (whatever adjective you want to put here that describes an irrelevant amount) proportion of the police force. In fact, a huge proportion of police were engaged in this exercise. Extrapolate that fact nationwide, and you see that no, it is not an extremely small percentage.
I am a pretty simple minded person that doesn't live much in grey areas - so I form my opinions a little different than others. I think the lack of respect for authority amongst people today (mainly youths) contributes heavily to the issues we are having. They don't respect police - we have tons of problems, they don't respect teachers - our schools are a mess and good teachers no longer want to teach, they don't respect the law - we have too much crime, they don't respect their elders - we end up with a society that lives by the "I don't have to listen to nobody" creed. For those of you that don't believe in respecting authority, I challenge you to tell your boss to "feck themselves" next time they tell you to do something. Your boss doesn't have an inherent authority over you, but he/she does within the confines of your company...it is the same way in civilized society with police, teachers and any other authority figure. You have the choice - and your choice dictates what happens next.

Your train of thought derailed at this point.
What world do you live in, that will be better if folks just learn to respect police? Like, what the feck? What gives you the impression that the police will act within the confines of their power if everyone just says "sir yes sir" and "ma'am yes ma'am"?
I am a big believer in change and would promote any change that makes all of us better - but it has to be done the correct way. Blatant disrespect and disobedience of authority is not the correct way to handle this. If you are harassed by police, teachers or anyone in an authoritative position - go through the channels and report it. If a specific police officer has been reported multiple times for instances, change should be made...if it isn't then we use community leaders and advocates to bring the issues up in an environment that isn't violent and doesn't drive a wedge between those that have authority and everyday civilians.
You're mixing two things here. Protests against police brutality have been mostly peaceful yet forceful in demand. The latest issue involved rowdy youth who were throwing loud parties. That was a situation that could have been resolved in a thousand ways without ending up shoving a young girl in the ground and brandishing a lethal weapon at 2 boys.
Lord knows this police officer would have remained in his post if the video which bypassed official channels was released. Says a lot about these "official channels" you place in high regard.
Two young black teenagers driving in a terrible area of town (before cell phones and GPS) trying to find our way to a friends house to pick him up for summer league basketball practice. Driving in circles not able to find the street we need to get to - after a few circles we get pulled over by two white police officers. In our minds we did nothing wrong, in their minds it was quite suspicious that we were driving aimlessly in this neighborhood. Police officers ask us to get out of the car with our hands up (area is known for gangs, drugs and violent crimes) - we comply - they move us to the front of our car and ask what is going on. We show them the respect we were taught to show - yes sir - no sir - they then offer to let us follow them to the street we needed to get to and pick up our friend.
I have been in many situations like this, and yes, you're supposed to act with respect, obey all lawful requests from policemen, etc... That being said...
Now much older, I often think back to that and have come to realize that it wasn't the police that were in control of that situation - we were in were in control. Our actions and how we treated the officers dictated whether or not the situation was cordial or combative. If we would have stormed out of the car yelling "why are you pulling us over - it must be because we are black" it would have turned out to be totally different.
You were not in control. I was not in control. The bloke who was killed while placed at the back of a police van was not in control. The guy with the gun is in control, at all times, and he will act as he pleases, whether you suck up to him or not. I have seen many examples of people throwing a fit at the cops; Reese Witherspoon a few year ago ranted at a Georgia cop, screaming, "DO YOU KNOW WHO THE feck I AM?", interfering with an interrogation of her partner. Was she manhandled? Was she assaulted? Was she killed? No, she got put in jail, and charged accordingly, for interfering with a police officer. Meanwhile, we cut to a man (black by the way) in North Carolina. Gets pulled over. Asked for identification. Reaches for it, and subsequently gets shot by a police officer. Miraculously he wasn't killed. And miraculously the police dash cam was running. Control? With all due respect, you control jack shit.
The fact remains that most of us live in a societal structures that provide authority to people within their job functions - I don't see that changing anytime soon. In the meantime we all have a choice as to how we interact with those who are given this authority. We can make the choice to work with them and respect the job they have to do or we can work against them and suffer the consequences - none of which I ever hope end the way we have seen lately.
No. The onus is on them to use their power in the right way. You have the right to walk down the street without being profiled. And if you're profiled, you can choose to lay down and take it so you can get on with your day. And you can also choose to bitch about it, and give the police an earful. Either way he better act right. If not hopefully someone is filming.