You aren't making an argument. You're using a non-equivalent parable and attempting to illustrate that there are two sides to the coin. You are wrong on many fronts, allow me to list them for you.

1) Putting a camera up in a public place is not at all equivalent to snooping in someone's email. There is no right to privacy in a public place. This is why people are allowed to take photos there. This is why traffic cams exist. This is why we have the freedom to peacefully assemble. Comparing a traffic camera to NSA surveillance is sophistry.

2) Observing a hit and run is not going to prevent a hit and run. It's going to aid in the prosecution of a hit and run after it has happened. The argument is "we need cameras so we can catch the people who are running over bicyclists." You've turned it into "we need cameras so we can prevent hit and runs." They are not the same. More sophistry.

3) Further, an argument put forth for the cameras is probable cause - "people are being skeeshed, we need cameras up so we can catch the culprits." The argument for surveillance bypasses probable cause - "we need to put cameras up in case something bad happens." I think this was a mistake on your part, but you know better.

4) Finally, you're obliquely attempting to make a point that not only attempts to undermine my own, you're ignoring the very argument I'm making. Simply put, for your future quoting fun,

Surveillance against law-abiding citizens is bad because laws can change and those who enforce them are imperfect, putting the citizen in danger of future criminalization for current non-criminal acts.

Your argument boils down to "but if they have nothing to worry about now, then they have nothing to worry about NOW." Your defense of this argument is "but people who have stuff to worry about now should be surveilled in public." Which nobody is talking about.

Your "anti-surveillance" argument is not, in fact, anti-surveillance. It's pragmatic. It says "perhaps we shouldn't spend tens of thousands of dollars and put the civil liberties of every citizen in Austin in jeopardy in exchange for marginally-improved prosecutorial tools against people who are already breaking the law." The amendment to it is "maybe we should park a police car at those intersections at closing time and nobody has to worry about a fucking thing."

See how easy that was? See how non-theoretical and clear-cut?