I have a feeling it was because you want to put the tanks in an unvented area inside your cabin. They couldn't meet the requirements of the law and were probably not going to take the chance with the liability issue. I feel you should revisit the idea of putting the tanks inside the boat with you...One month ago I contacted all the bladder tank manufacturers via their web site contact pages. Asked about having two custom tanks made. Only one responded and "dropped" me as soon as he learned I have a small boat (26X)..