bmcgee - 7:36 pm on Feb 12, 2013 (gmt 0)
The options are:
1) go without password and just put them on the mailing list via the service
2) create an account for the user on the client's website, for convenience in placing future orders and giving them access to other email option not available on the mailing list service
So password is not required, but they lose functionality by the user not getting a website account created.
So the question is how much of a deterrent it truly is, to balance against the benefits.