Sometimes I see login at the top right as if I wasn't already.
Example.
I am logged in now but If I go to the homepage it says login at the top. When I return to the forums I am logged in again.
For a while I would just keep logging in and then discovered I could do anything that required membership even when it said login at the top.
You might want to ask the mods about this, but I noticed it changed too about the same time Kevin mentioned they were experimenting with how the advertising was fed.
When I first open the Crackberry site on the forums, I am not logged in, but when I click on a thread it logs me in and thread section gets wider when the adds on the side are not there.
I intentionally do not use the remember me box when using the playbook because I like using the default view, and prefer the wap (mobile) view on my 9930. It may be a single device only option. Try logging out with your BB, then login with your playbook and check "the box". Just a thought!
Posted from my CrackBerry at wapforums.crackberry.com