Sure.
We have to distinguish between somebody being charged with an offence and someone being convicted. In my experience, I've seen many cases where individuals are charged, but then the charge is withdrawn or they're acquitted after a trial.
The threshold to lay a charge is reasonable and probable grounds, and particularly in a province like Ontario where charges don't have to be approved by the prosecutor, you're relying on the policing policy and the individual knowledge and experience of the first officer to respond to a scene. Particularly where a firearm is used, or where there has been a violent incident, often I have seen that the first instinct of the officer is to lay a charge, and then say, “We'll let the court sort it out.”
The trouble with that is, of course, as I said, that the process is the punishment. This means a person is going to have their liberty restricted, sometimes by being placed in custody, strict bail conditions and an incredible expense, not to mention the stigma that's associated with having criminal charges hang over your head.
So it begins on the ground level, and it doesn't matter if you're acquitted or vindicated. Clients always say that no one remembers that follow-up small-print story at the end of the day. People remember the front-page news when you were paraded off in handcuffs for exercising your right to self-defence.