This happened to my nephew when I was riding with him in Washington near Spoken, except it was a regular two-lane highway, not a freeway. The car was an unmarked, and an old Chevy Caprice, at that. It was going just below the speed limit up a hill, nephew passes. Car speeds up a bit and appears to be "pushing", so my nephew sped up a little bit to put some distance between them. Car appears to be pushing a little more, my nephew started getting a little bit steamed about it, so he speeds up a little more. Flashing lights come (in the grill), speeding ticket issued. In retrospect, my nephew should have just continued on at the speed limit, but he felt like he was getting pushed, which it really looked like he was.
Overall I think that all traffic ticket income should go to the state department of transportation, not the state or local cops. You just create too much of an incentive for the cops to abuse the system with the way speeding law is enforced.
I know in MA there was a major stink a few years ago when a memo from the state police chief to the cops on speeding details to make their ticket quotas or else was leaked to the press.