Probably as an aviator , and a huge fan of the pilots that had to fly and fight over North Vietnam in that ridiculous war, I am as thankful as they were that he negotiated the release of the vast majority of those shot down and going through a living hell in the Hanoi Hilton. That was all Kissinger. 11 days of B52 bombing over Hanoi in Christmas '72 didn't hurt in concentrating minds either.
Children under 18 can't be banned for overstay BUT children OVER 15 ARE fined for it
So you are correct, they would pay 20K baht fine when she leaves <- AND she needs to leave BEFORE she's 18 even though she's thai she's not HERE as a thai she's here as foreign child