Don't think this cabotage -- you are going from Mexico to LA (very indirect routing). You would not be able to book -IAH-YYZ-LAX as a single ticket as that would be cabotage.


Another example -- Alaskan glacier cruises start in Vancouver, CA and then stop at various USA ports (Juneau, Sitka, ..) on their way to Steward / Anchorage. The cruise lines does not have to be USA registered and are not commit cabotage in connecting to various USA ports due to the start from Vancouver. They could not do that starting from Seattle.