That sailors on small boats that come and go at irregular times and arrive from exotic ports are probably a very tiny minority. Probably so small as to "fall through the cracks" from time to time as larger issues are worked out... such as how to handle a whole plane load of people and spot THE potential terrorist.

I run into similar issues in the bicycling community... where regular cyclists represent less than 2% of all transportation in the US, we on occasion run into issues like why don't certain drive-thru establishments allow cyclists but do allow motorcycles.

Here again, cyclists represent such a tiny sector... they tend to be overlooked when rules, etc. are put forth. Just as individual sailors on tiny boats.