The USA *never* give up their citizens for trial abroad - whether in the kangaroo courts of the People's Republic of Rumbabwe, or in the cradle of democracy here in the UK - they just don't.
In the old days this woman could have just quietly got on with her life - the US press wouldn't bother to cover the issue and so her anonymity would be quite safe in the good ole US of A.
I live in hope that, nowadays, she will be consumed by the internet social media whirlwind and she will hopefully be hounded from pillar to post and her life will become intolerable.
I'd put money on a 'leak' of the relevant footage if she doesn't find the streak of decency that would have her returning voluntarily to the UK.