I have been using the K&N air filters since 1988 and have always cleaned, dried,and oiled them before reinstalling in accordance with the directions that came with them.
I couldn't even begin to count how many times i've done this procedure, and now i find out it wasn't necessary.
It'd be nice to have a dry filter that doesn't contaminate the maf/IC/TB/IAC. On my K&N I taped it to a shop vac for a while to suck out the extra oil. Still get a bit of film when I pull the up pipe.