I imagine it's more of a "check this box to verify you are not a US citizen" system. The bank could then charge your account fees if you lied and they had to deal with the IRS.
I actually think the US tax return laws are reasonable -- there have to be some obligations for citizens to go along with the rights they have.
Two reasons, first off the US government can request banks abroad put a hold on US citizen's money. Secondly if you ever enter the US they can hit you with fines and interest.
There are many people who do not even know they are US citizens!
Every kid of an expat may not know they are actually considered naturalized US citizens. In fact, the US Consulate won't even tell you the truth!
The US gov will make substantial efforts to help you if you're caught in a war zone. That's a big plus if you live or travel to dangerous areas. I'm a Canadian, but I've heard stories about people working overseas with other foreign workers. When things get bad the American's are quickly evacuated, other not so quickly.
Also if you ever move to the US you immediately, or at least very quickly, qualify for programs you never paid into. Medicare if you're old, in state tuition if you have kids, etc.
But US citizens living abroad have to file tax returns even when they don't exercise that right. They could live abroad for the remainder of their life and have to file (under IRS rules).
That seems like a very flimsy argument for why US nationals abroad have to file tax returns.
I actually think the US tax return laws are reasonable -- there have to be some obligations for citizens to go along with the rights they have.