There are enough documented cases of police over-reactions, including cases where there was no criminal history.
Jonathan Login is a classic case.: http://www.cdnshootingsports.org/JonathanLogan200603.html
I routinely drove through Baxter on my way to and from Borden daily. I was going home one afternoon while this was still simmering in the local media and courts but was no longer major news, via our babysitter's house in Barrie. For a little variety and because it was a convenient route to her place, I took backroads. Unnoticed by me, an isolated stretch dropped to 50 from 80 for no logical reason, and I missed the sign. Two OPP constables leapt from the bushes, and directed me into a gravelled area in the trees. There were a couple of other cars who'd been pulled in as well. I was surprised to be told that I was speeding, when I was doing 70 in what I thought was an 80 zone. I apologized, and expected to be let off with a warning, especially as I was wearing my flying suit. The female constable interrogated me at some length, asking me why I was driving along that route, and pushing me to admit that I was coming from Wolf's Den. I've never been there, and was not very sure where it was. Her attitude, especially as I was in uniform, baffled me. Receiving the ticket was also a surprise, but I was not going to make a fuss.
As I continued on my way, I realized that she was probably clueless and did not even recognize my uniform, mistaking it as hunting clothing. I still believe that it is highly probable that this was a traffic ambush to harass Wolf's Den customers during the fund-raising efforts. There was no other reason that I can see to spend time like that out in the middle of nowhere, when there were more highly-travelled routes around that would generate more income.
http://www.cbsnews.com/8301-504083_162-20025657-504083.html
http://articles.businessinsider.com/2011-08-16/europe/30052167_1_essex-police-social-media-youths
http://www.independentsentinel.com/2011/11/armed-police-a-toy-gun/
http://www.dailymail.co.uk/news/article-1135179/Armed-police-arrest-man-playfully-pointing-toy-ray-gun-baby.html
http://www.cbsnews.com/8301-504083_162-20100289-504083.html
I've been trying to find a couple of better examples of Canadian police over-reactions that have featured in the news. I'll have do a more detailed search later.
When I was a child, every boy had at least one cap gun, and could freely play with it outside his house and on the street with a bunch of similarly-armed friends with no fear of being surrounded by a black-clad tactical team with real weapons, forced to the ground, cuffed, and tossed in the back of a police car.
One fatal shooting in Woodstock, Ontario sometime in the 1980s comes to mind. An OPP TRU team went to the wrong address very late one night to conduct an arrest. I do not recall the reason. The house was surrounded, and the TRU team was dressed in camouflaged clothing. The homeowner was awakened from outside the house, but the TRU team did not clearly identify themselves as police. The homeowner, who had been drinking earlier, believed that he was being threatened by thugs and went outside with a rifle. The situation ended with the homeowner dead and at least one OPP member wounded. They had gone to the wrong house. The intended target was the one next door. Oops.
In most over-reaction cases, a simple polite knock on the door and a chat - during daylight hours so that the interviewee would be less dazed and confused and feel less threatened - would establish what had really happened and avoided needless tragedy or mental trauma.
In many cases, such as the Login one, there is clearly no threat to the police who are responding.
Police make mistakes, including major over-reactions. They are not right all of the time.
http://www.cdnshootingsports.org/2010/05/CSSA_Release-Police_Relations_Survey_20100527.html
The mistrust has been well earned. I understand it. I feel the same way, even though I should not, as I posted earlier.
The whole act has to go, the stigmatization needs to end and be reversed, and the police have to re-learn that calm and good manners will save lives and alienation and that honest citizens who used to be their biggest supporters should neither be viewed as easy pickings nor as the enemy.