I'm sure many (like me) don't like the idea of having to use an authenticator to login, but its necessary in order to use the RMAH.
here's what happened:
1. I tried selling an item, needed an authenticator.
2. Attached an auth.+ SMS security.
3. Posted item for sale for Paypal
4. Removed authenticator and can still post items through Paypal
Try it out guys, let me know if it works for you too.