I guess we need to find an ultracompitative ass-hole and get his opinion on what he would do.
With my old car (it was kinda beat up), I'd hold my position if I had right of way and felt that the other car had done something improper (i.e. go into the ending lane, floor it to pass half a dozen people, and then try to force back in; or they blew through a left/right only lane to try to get ahead; or... you get the idea).
Every single one of them backed away; most hit the brakes and fell behind, a few hit the gas and went further ahead until they found somebody they could force.
I could have merged but didn't because this guy was going so much faster and I didn't want to cut him off as he didn't appear to be slowing at all despite the string of cars in front of me that had already merged in front of him (and in front of me). 