Hmmmm, very interesting question !
I don't see what K&N filters would have to do with gumming up the MAS
I could possibly see it if you soaked the filter with oil before install. Done properly as per instructions on cleaning and re-oiling, I just don't buy it.
I've run K&N's on my 01 Harley, 94 Dodge Ram and now my 04 XFire for years with no ill effects.

Just my Dos Centavos !