If a user:

• does not check "Remember me"
• fills in the issue creation form
• leaves the computer for an hour
• returns to the computer and clicks 'Submit'

then they are likely to get a confusing permission error, because they are not logged in anymore. If anonymous issue submission is allowed, the issue may be submitted anonymously, which is not what is wanted.

Ideally JIRA would detect that the session is expired, save the current form data (in a new session's attribute), redirect them to the login page and return to CreateIssueDetails.jspa without losing any of the previously entered data.