IF an NPC tries to knock out a PC (or vice versa) and reduces her to 0 hps she is unconscious and stable. Would you allow her to make Stabilization rolls anyway in hopes she can roll a 20 and gain an HP and wake up?
Maybe the npc's were not that accurate with their calibration of the "tap" to the head. Literature/movies are full of hero's waking up at a time inconvenient to the bad guy. The randomness give you a chance to avoid being trussed up like a Thanksgiving turkey.
No. You're unconscious for 1d4 hours or until healed.
Why is 3 fails still "unconscouns"? I would have thought that if you're allowing dice rolls, then there should be consequences for both success and failure.Sure, I'd just run it like death saves. 3 successes before 3 failures. If you fail your "consciousness" throws then you're simply knocked out for at least 1 hour (a short rest, at which point you would regain 1 hp). If you succeed 3 times or get a nat 20, you regain consciousness at 1 hp.