Generic Customer and Generic Technician Duplicate Error with Same email

I am trying to create a generic Customer called "Walk In" and a generic technician called "Horoligist"

I want to use the same email for both [email protected]

However, when I try to save the Technician, I get a duplicat entry error - 

Please advise

This would not be possible to use duplicate emails as per WordPress do not allow this and Emails are unique identifiers for the users as well. I would request you to use different emails . You may use [email protected] for technician and for customer [email protected] 

Understand, it would be nice to not have to add "Generic" Users and Technicians (as your video suggests)

I really did not want to add any "Users" to my site, except me... :-)

If the only option is to add the emails, I will do so...

Thanks