email generates issue assigned to invalid user

I created an e-mail by sending to a recipient who is a JIRA user, and cc'ing the email address that is used to create an issue for a project. The idea was to send an email to a number of people, and also create an issue at the same time. Everything worked great except that the issue was assigned to the individual who was listed on the "To:" line of the e-mail. I would have expected it to go to the default, which is the project lead. The issue, then, was assigned to someone who is NOT an assignable user for the project. I would add that as the creator of the issue, I do have permission to assign users whereas not all users do.
So I have 2 questions:
1) Why did it assign the issue to the email recipient in the first place, since I didn't see that in the documentation (http://www.atlassian.com/software/jira/docs/v3.0/issue_creation_email.html)
2) Why did it assign it to a user who is not an assignable user for the project?