I used to think the same thing when I lived on Maui, but later discovered they were spraying off shore and letting the trade winds blow it across the islands. On those rare wind-free days they would actually spray right over the island. If you watch the movie "What in the World are they Spraying" you'll see their investigation on the effects this off shore spraying has on organic crops on the east coast of Maui.

Also, when I was flying from the islands to the mainland once I saw a chemtrail that stretched for miles and miles above open ocean. That really made me realize that this agenda was not just targeting land masses.

As much as I'd like to believe they're not spraying Kaua'i, I think it's just a matter of it not being a visible phenomenon.