I did read the OP and his friend went to move over but the guy behind him couldn't wait till he moved over so the rager probably cut someone off to get in that lane. The friend was probably waiting till he had enough room to safely move over the rager didn't care about safety. I see people cutting others off on a regular basis. You've got people that will be in the left lane and all of a sudden they cut across the other lanes to make an exit at the last second. As I've said in my prior posts if the person in the left lane is passing they have a right to be there and that they should move over when safe to do so but there are those on here that want the person to cut people off so that they can get to where they are going a couple minutes faster while endangering everybody's life in the process.
True, but go back and read the OP. The right lane was not solid cars as evidenced by the fact that the friend did move over, and that by the time he did there was sufficient room for the rager to have already moved over.
If I'm passing and someone comes up on me tight I try to signal as soon as I see there's going to be a slot to move over, and I start moving over as soon as I see the headlights of the vehicle behind me are even with the car on the right. That's closer than I normally like to merge back in, but I want to be most of the way into right lane before the tailgater has room to cut right and around. Many left lane campers won't pull over until there's a clear quarter mile stretch to pull into, or even half a mile if there's a truck up ahead.