Hi:
Since Information Maps use the Workspace server and since Stored Processes that use Information Maps also need to use the Workspace server and since the Workspace server, in some configurations, uses this information to authenticate/authorize the user, then the use of the ID and password may be required. It does depend on the configuration of your Workspace server.
The best place to get these questions answered is to contact Tech Support, because they can help you figure out exactly what is happening and whether the default is required, and whether there's a workaround for the issue -- given your particular configuration environment.
cynthia