Suberman - I think smbrm is just testing you. He does that to me sometimes if I mis-speak.
I believe the above statement is correct in that the fuel displaces the lubricant. Fuel dilution thins the oil, but doesn't necessarily cause "shearing" (as I understand it).
http://www.amsoil.com/techservicesbu...20Dilution.pdf
It's probably worth mentioning that Blackstone, the most popular uoa lab on bitog and here, doesn't actually test for fuel. They extrapolate the fuel % from the flashpoint reading. It's probably fine if your BS fuel % is low, but if it starts to creep up just keep in mind that a BS type fuel reading will usually be lower than the actual fuel %.
More reading here:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=968027
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=4637
And note the comment about engine mods and performance chips in the Amsoil document. This is something that folks should keep in mind, if they mod their car and/or race it as Suberman has eluded to. And no, running 5W-40 isn't the answer either.
-Dennis