Please make the user passwords case sensitive.
The password "PaSsW0rd" is functionally equivalent to "passw0rd".
This was most recently tested in 9.2 RC.
Nice pick up - I normally use LDAP authentication, but just tested this on 9.1. I can log on to DPA using a custom account with all lower case instead of the correct mixed case. Passwords on custom alerts however, do use mixed case.
I'd be inclined to lodge this with support rather than as a feature request. I'd call it a bug, certainly a potential security issue.