I had to dig around the internet to figure this out... but there are states in the US that require you to register a party affiliation in order to vote, right?

So, that sort of answers my question about how on earth anyone would know who you were voting for... but I must be missing the leap between having a registered party preference, and that magically embedding itself into your medical records. Am I missing something obvious?

What about states where you don't register a party affiliation? What about people who don't vote at all? (Or is everyone registered, but voting is optional?)

Sorry, far too many almost-sensible questions from me.