All I can think of is that it is infact your internet broswer. I tried going back and what not after logging out and it wouldn't let me.
Basicly your cookies arn't clearing correctly when you log out. There isn't an option I can see within options to clear the cookies from your actual Redcafe account.
What I suggest you do is go into the options of your internet browser and usally some where around in there is a button which allows you to clear cookies. Would give a more detailed explaination but obviously it varies from browser to browser where the button is, but if your on Microsoft then under the tools menu then options and in there somewhere.
I do however warn you that if you do clear these cookies, anything you haven't logged out of or any site that remembers you or say a game score or whatever. Anything that associates you with a website, will be removed. So you will have to re-log into sites and so on.
Thats the only thing I can think of I'm afraid. Whether it works is another matter.