Yes, that is right. As an exchange admin, you don’t have to type in a password when you create a resource mailbox in Exchange 2010 SP1. The password boxes are greyed out.
It is a good move as resource mailboxes are not meant to be logged into! It will save few seconds too . You can reset the password of the disabled resource mailbox account using AD Users & Computers, if there is a need.
Passwords are still needed in the latest pre-SP1 build, Exchange 2010 with Update Rollup 5!