Ah, that reminds me of another behavioral trait, most commonly seen with drivers of expensive "Euro" cars: You pass them because of their slow pace (usually yapping on a cell phone) and when past, they suddenly decide to drive 10-20 mph faster and sit on your bumper, if not to try and pass you back. An ego thing most likely.........
I drove cross country any number of times by getting in front of guys in Beemers and then very slightly slow dowm. They'd shoot out ahead, and I'd pace them at a distance. I'd be far enough back to see them getting pulled over. I'd then look for another "rabbit"..I practice "stealth driving"..