Hi,
A typical problem in multi-journal installations is that a user has registered to journal A and later want’s to submit something to journal B as well. However, usually this is not possible, because the user does not have the author role in journal B.
Now I know that the user can edit her profile and add that role, but that is simply way too complicated for many users.
My suggestion:
When going to about/submissions
page in journal B and clicking the Make a new submission
button the user should get an opportunity to register herself as an author to journal B.
Basically instead of seeing this "The current role does not have access to this operation"
the user should see something like "You are not registered as an author in journal B, would you like to register as an author?"
and should have a simple button to perform this operation.
This would of course depent on the journal settings, whether it is possible to register as an author.
I know that "The current role does not have access to this operation"
is a general message used for several similar cases, but I do find that this case is an exception and providing this mechanism would cover most of the problems with multi-journal user roles.