I don't get why these companies would want to keep employing someone who has stated that they want to quit.
if I was a douchebag boss, I would manipulate them into staying then publicly reprimand and fire them shortly thereafter to come out a "winner" in the situation. I haven't seen managers stoop that low yet, but state-side I've seen managers take extreme personal offense and paranoia about team morale when there was even one flight risk on the horizon. (omg they didn't even pay $100k for their once-in-a-lifetime chance to exercise our magic stock!)