Thoughts on a GMRS License "Grey Zone"

Just curious… A GMRS license state that all immediate family members are allowed to operate under your license. How does a repeater owner distinguish who is your family member? A user can say a friend of his who is not licensed is a “brother, sister or even cousin”? How is this enforced? Seems like a very untalked about topic in GMRS licensing. Thoughts?

Just follow the rules… The licensee is responsible for all communications under his/her license.