All in ZWC 5.0.18:
1) As user1, add share of /Calendar to user2, view-only. Send default email.
2) As user2, accept share
3) As user1, edit properties of /Calendar to grant Manager privs to user2. Send default email.
4) As user2, accept share.
Results: "Folder user1's Calendar already exists."
We could opt not to send the email, but then user2 doesn't get privs until browser reload. Deleting/recreating the mountpoint is even uglier.
Is there a bugzilla for this? 6.0 changes a lot of share browsing behavior... is this handled differently there?