The Surgeons Knot is just a standard shoelace tie with 2 slight modifications - when you overlap the 2 sides of the lace you tuck the lace under twice. This, like a Timber Hitch, creates much more contact area and thus much more friction.
I have (not from that site) switched the way I tie a standard knot as I was doing grannies instead of reef-knots. This seems to have prevented unwanted unties.