And what's going to stop Mom and Dad from swooping in and dragging junior back home?
Once Junior or Junie gets to GA, for example, he is an adult.
No one, that includes mom and pop, can drag him/her anywhere without penalty of law.
The law is a very quirky beast.
The person is a minor only in AL, until majority is reached at age 19.
However, an 18 year old in LA or TX, for example, is a member of the majority.
He or she is an adult.
He or she can set up housekeeping or simply become homeless.
AL would no longer have jurisdiction over an adult residing in TX.
Heck, at age 18, the person could obtain a US Passport, buy passage on tramp steamer to Malaysia, and simply disappear.
I make no recommendations in this matter.
I am simply reciting the law, as it would apply.