Affordable Care Act for Americans living abroad?

I think I'm starting to wrap my head around the Affordable Care Act.    Before today, I knew a bit about it, but all I was really cared about was that it was great for friends and family back home who weren't insured and that's all I thought mattered.... but now I'm beginning to wonder how we're affected living abroad. 

Does NHS cover the insurance requirement for Americans living in the UK?  Will we be asked to prove it somehow when we file taxes?

Besides my questions, I found this video that explains it quite well (and in an entertaining way!).

http://www.upworthy.com/the-simplest-explanation-of-obamacare-ever?g=3&c=fea

There is an exemption for those who can file as a bona fide resident of another country.

https://www.healthcare.gov/am-i-eligible-for-coverage-in-the-marketplace/

Depends what type of visa you are on... most of them cover NHS expenses