> and you're expected to keep up with the flow of traffic.

This is very state dependent, if we are talking about legality.

In WA state, for example, there is no "flow of traffic" law or similar. The limit is the limit, and any excess of the speed limit is illegal regardless of what all other drivers are doing. So even if the right/slow lane is going 100MPH through the 70MPH zone, you are legally expected to still go 70.

Thankfully we do have laws against left lane camping, but I rarely see it enforced.

You’re confused. If you know of ANY US state that has a flow of traffic law that allows cars to exceed the speed limit so long as they are keeping up with other traffic, I’d love to see a link to their traffic codes. Speeding doesn’t suddenly become legal because two or more drivers do it together.

This has nothing to do with the expectation that slower traffic stay in the rightmost lanes, which is what GP is addressing.

> This is very state dependent, if we are talking about legality.

Are you sure? And by that I mean, are you sure there are states that don't work the way WA works?