> You have to go through security again for international flights that connect to a domestic flight, but not usually (ever?) if you've passed TSA within the US and are connecting to leave the country.

There are lots of times when with domestic -> international flights (or even domestic -> domestic, in some cases) there would be terminal transfers required that would leave the secured zone and thus require passing through security again incidentally, even without a specific policy.

Several airports where I know this was an issue have been redesigned to alleviate this, but I'm sure there are some where it is still an issue.