What stops someone from taking a shot of a foe's license plate and submitting it out of spite?

The same thing that stops people from filing bogus legal charges against their enemies: a structure that holds them responsible for their claims. As with most social-media functions that allow people to shine some light on uncivil behavior and/or criminality, there's a need to balance accountability and anonymity. Ideally there'll be accountability in both directions: whistleblowers will sign their complaints. The right to know your accuser is in the Sixth Amendment, and this app should be designed accordingly.

No system manages the incentives and disincentives perfectly (for example, how many assaults go unreported because a victim figures the legal system puts plaintiffs through too much trouble and grief?). But with a crowdsourced accountability system for dangerous drivers, even if the crowd can't/won't catch all of them, it will catch more of them than the NYPD currently does, which unfortunately -- with all due respect to the officers who do their jobs responsibly -- is hardly any of them.

Check out DriveMeCrazy, or maybe Roadify