Custom certificate (plugin)

I'm running Moodle 1.9.7+ with the 1.9 certificate module. I have a site-wide registrar role which is able to register people on the site but all the registrars are receiving the certificate notifications when someone gets a certificate.

I'm guessing there is a permission setting for registrars that makes them look like teachers. Can anyone tell me which permission setting I can turn off so that they do not receive the emails?

Thanks!