Note also that that 100 miles _is a radius around your nearest international airport_ and need not be what you think of as a border, i.e. a line drawn between two land masses.
Please cite a reputable source for this claim. Preferably a SCOTUS ruling.
This is not correct, it’s a common but false misunderstanding. The text of the law does not support this and the ACLU/EFF don’t see it as a likely problem.
People should stop repeating this claim or it will become one of those “folk truths” that eventually becomes accepted and real.