in form V6, you have a "User Anonymous" function. You can setup a process with this properties, and then any person can create a case without a Bonita user/password.
You just need to give to the user an URL like:
This is a behavior close here. You configure in the filter a user/password. Then, when this URL is call, if the user is not connected, the filter do an autologin, and the user can create the case.
The filter works on a task do, and (on configuration) can perform a automatic assignement : in V7, if you try to execute a task before any assignement, you'll get an error (so, give the URL task in an email for example, will never work).