Properly oiled cotton based filters are just fine as long as the person thats servicing them doesn't soak the media in oil until it's dripping. That's the reason the oils are in a aerosol can. This is taken from the manufactures website;
Lightly oiling each filter pleat and allowing the oil to impregnate the gauze, 6) Allow to set for 20 minutes, 7) Checking and re-oiling the light spots
This link is from the FAQ about MAF sensors...
http://www.knfilters.com/faq.htm#17
There are links to MAF tests they conducted...I don't think there's a connection.
I have K&N's on all my vehicles and have never had a problem.
P.S. I can see my Outerwear (air filter) by just looking in the side vent. What I would like to see is the pipe turned and the filter in the vent opening and sealed off at that point. Cleaning the air filter would simply consist of removing the side vent cover and removing the filter!