Both lanes have to be filled right up to the merge point. The asphalt exists there for a reason. I don't understand how this concept is so difficult. Fill up both lanes and merge at the last point. This way the congestion is shorter than if you leave a large section of a lane unused.

A better example of efficient asshole tricks can be going off to the gas station when the highway is congested and reentering the highway having simply driven through the gas station and this way jumping the queue.

Using all that asphalt doesn't increase throughput at the chokepoint, right? If the queue is long enough that people who want to exit before the chokepoint are needlessly prevented from accessing the exit, then using all the lanes could help, but it won't get anybody through the chokepoint any faster that I can tell.

I imagine OP is more describing e.g. the backed up 1-lane highway exit, where the second lane is clearly for through traffic. Uber drivers in that situation will often drive straight to the end, signal, completely stop, and just wait for someone to let them in.