[fchollet]

This would de-incentivize the reporting of infractions, which is the opposite of what you want.

You want to incentivize the reporting of verified infractions, while de-incentivize false reports. A consensus system could be used to "verify" a report.

[kmkemp]

In this kind of system, I think the negative points are to remove the burden of confirming infractions. It's in an individual's best interest to both keep driving AND to remove poor drivers. Hitting the correct ratio is the key.