NullPointerException thrown when clicking the "Start" watching link in the "Manage Watch List" panel and not logged in

To reproduce:

• Have an issue with at least one user watching it
• Do not log in
• Call up the issue
• Click on the 'Watchers' link
• This will display the "Manage Watch List" panel:

Manage Watch List
On this page you can manage the watchers of the issue QA0000-62.
Start watching - you are not currently watching this issue.

• Click on the "Start" link
• A NullPointerException is thrown