[CfC] close annonymous commenting to tickets?

1. It's not actually a task to change, but to gather comments or suggestions.

In previous environment, to make things easier, we enabled anonymous comment to JIRA tickets. Now we are open to register from public, anyone who are interested can register and comment as logged in user.
I think it's time to disable anonymous comment, especially to make failure of ourselves as small as possible. How do you think?