Next time you see a high refresh screen, move the cursor around rapidly. It's very easy to tell.
In gaming situations what they perceive may not be the actual "flicker" of frames but the input->to->display latency, which is a very different thing to notice.
The jumps from 30-40-60-72-144 are all pretty noticeable, but 144-240 is already very minimal and 240-360+ is pretty much quackery.
Next time you see a high refresh screen, move the cursor around rapidly. It's very easy to tell.