There's a fine line between cya and being a selfish paranoid person... Learn to walk the line personally I've only done this once and I woke up not feeling too hot but I was fine for the flight home. That's exactly what I told scheduler. If I do get a violation or into an incident/accident, what is so hard about defending your judgement? Of course cover yourself in handy wipes for the sake of ther crew members. I'm not company guy at all, but I do care about not messing up passengers' plans/connections/other offline pilots commuting home, etc...