Just recently, I was told of another way to completely remove Exchange Public Folders from appearing when using Mail.App (or any IMAP client). This is not exactly a 'Mac OS X' hint, as it involves making a change in Windows Active Directory. Therefore, you'll have to coordinate with your network administrators and request this change. Since I am also the Network Administrator, I was able to make this change myself ;).
Here's what I did:
- As a Domain Administrator, you have to run the "Active Directory Users and Computers" MMC snap-in.
- Find the user account you wish to change and select "Properties".
- Select the "Exchange Features" tab.
- Select "IMAP4" then click "Properties..."
- Un-check "Use protocol defaults."
- Un-check, "Include all public folders when a folder list is requested."
- Click "OK" twice to save changes.

