I'll paste again,
http://www.samsmarine.com/forums/showthread.php?t=8068 Go to the second page to see the actually "engineering theory".
A bolt with enough preload is unlikely to loosen. Again, these nuts are softer than the shaft, so I doubt proper preload on the shaft can be obtained. In fact, 100ft lbs of torque really isn't that much at all anyway.
There is a "right" way, but in this case I doubt it matters. Comparatively, the nuts really are not tightened that much...(think semi wheel lug that is at least 300ft lbs).