You are right. But "leaving it alone" has its costs to society too. After all why not just really "leave it alone" and ignore the woman screaming from the shrubs, or turn up the game on the TV when you hear gunshots outside. And no need to waste time, just tell the police officers you really didn't see or hear anything when they show up to investigate the body in the street.
There are neighborhoods where the residents "leave it alone" all the time. I doubt you would want to live in one.
Oh, and there is zero evidence that every mistake made by law enforcement officers prevents a potential crime either. I presume you wouldn't use that as a basis to recommend that law enforcement officers just "leave it alone" when they see something that is to them suspicious.
Had Martin done any of those things you described, there would be no issue whatsoever. I would go even further and say that if it turns out Zimmerman saw Martin looking into parked cars or checking into people's backyards, then he would be completely justified in following Martin. But again, so far, there doesn't seem to be evidence of actual "suspicious activity" to warrant Zimmerman's decision to pursue Martin.
You are right. But "leaving it alone" has its costs to society too.
...as do poor decisions...and look what this one has turned into. Sharpton couldn't be happier.