was told that ALL dual flights require a visa. That didn't ring true, as I thought that people who were doing a rental check-out or BFR didn't need a special visa, but of course I don't have a reference to the "official" document...
If you look
here, there is a TSA letter that is relatively recent (Oct.19, 2004).
The letter confirms TSA's position that "flight training" means "only training that a candidate could use toward a new airman certificate or rating". Accordingly, the new "Alien Flight Training/Citizenship Validation Rule" doesn't apply to rental check-outs, conversion training on light aircraft (i.e., training that does not lead to an official type rating), or BFRs.