When you assign a case to a user it would be nice if FogBugz provided a warning when that user won't have permissions to view a case.
Today I assigned a case on an internal initiative to a newer developer and didn't realize the user hadn't been granted rights to this group yet. He received notification he was assigned the case but when he navigated to it just got the error
You do not have permission to see case #123.
When assigning the case I should have received a warning.