The CSS below can be added to your child theme's stylesheet (CSS file) or via a plugin like Reaktiv CSS Builder or Simple Custom CSS.
/* Hide the copy attendee checkbox option during registration checkout */
div#spco-copy-attendee-dv { display: none }
Thanks Lorenzo - that worked perfectly!
Wondering if there is a way to have the registration form not ask for the primary registrants info every time there are multiple attendees (Example - 1 parent 3 children attending event)?