Is it against the law to have unlicensed cars parked on the street?

This is a good question Lyneta Unlicensed cars are a good example of what you can report, Its up to the officer to issue a citation based on the details that come back from a VIN check. So it isn't always against the law it could very well depend on the origin as previously stated.

Yes it is against the law . it is also considered to be an abandoned vehicle which both can result to be towed to the impound lot

Yes it is