A 5 mph differential for a long line of vehicles is not a reasonable rate. It's micropbutting IMO. If my pbutting differential is limited to 5mph because of safety, I simply don't pbutt. I wait until it's safe to pbutt at good rate.
Also, I've found that in long lines there are usually places to move back right and let faster traffic pbutt. A driver like yourself would get flashed by me after ignoring such opertunities.
Yes, I do use them when I see someone gaining on me and I do not wish to accelerate to complete pbutting the line of vehicles before he reaaches me. I will be out of the left lane before he reaches me.
Many LLBs are about being first and nothing more. A few days ago I encountered one who accelerated to tripple digits to catch up with me and repbutt.
But then again, unless someone is directly blocking my path I don't have anyone catch up to me and get on my bumper. What happens to you simply never happens to me.
Hmm... so you are 'peeed off' by a behavior similiar to one you consider reasonable and do yourself. He's probably pbutting at what he considers a reasonable rate.