I did once refuse to fly an MD-11 from Anchorage to Seoul, long time ago, at Gemini.
It had a deferred engine generator and a deferred APU. Yes, it is possible to divert along the way in the pacific tracks, but it was at night in the dead of winter and I just didn't feel good about it. No questions were asked, and the mechanics were actually grateful - they wanted time to fix the plane....