Why Do I still have a CEL after installing 02 Bung Extenders?

prometheus036

I'm trying to avoid a tune so I can keep the warranty for now, once it expires I'll look to do that. I was under the impression that backing the O2 sensors out of the exhaust stream would trick the ECU into thinking the correct Air/Exhaust mixture was there. I've heard people say to use steel wool as well to bypass it. Does that actually work?