You know, I honestly don't know the answer to that question, although I've thought about it many times. I've always used knots that only passed through the eye once (improved clinch for mono and now the san diego knot with floro). I tried the trilene knot for a while but it just seemed like extra work for nothing since it didn't seem to perform any better than my improved clinch.

I haven't experienced a lot of breakoff problems in my life so I stick with what works for me, though many can probably say the same of their experience with knots that pass through the eyelet twice. Someone somewhere has probably done a scientific study of this, dunno.