Cannot prevent calendar entry deletion

I have a shared calendar database based on the Notes 6.5.2 email template. I cannot prevent calendar entry deletion! No matter what I set a user’s ACL to, whenever anyone hits the “Delete” button, the selected calendar entry disappears from the database.

Where is the code that is doing this and how do I stop it???

Subject: Cannot prevent calendar entry deletion

If they have “Write Public Documents” privilege, then they can delete them.