It works just fine, I've ran it for sometime. The cat isn't "blocked" persay, just not removing hydrocarbons and such as it should. That's what the o2 sensor is telling you, not that it's blocked in any way. I could care less if the catalyst is working in there.
I've been running mine for over a year, no problems. I don't even have a cat and it works fine. Skabone and I know our head from our ass when it comes Honda's, Accords specifically.