On the front-end Manage Registrants page the button labels are misleading. I suggest the be renaming the 'Publish' & 'Unpublish' buttons to 'Paid' & 'Unpaid'.
I have changed them in the Language settings but this also changes them elsewhere such as the Manage Events page where they should be 'Publish' & 'Unpublish'.
That's standard Joomla buttons, so I will leave it as how it is for now. If there are more customers request for this change, I will try to support that in the future