Add only registered customers as program members for webinars

Currently, if we use A/B testing in the webinar emails, all the invitees are added as members of the program and a workaround suggested for this was to create an email template for A/B test in design which is not the ideal way. 

Having an A/B test should not affect the way members are created for a webinar program.

It would be nice to have a standard way to classify people as members regardless of A/B test or not.