90% of your problem can be fixed by you ponying up for the &quot;extra leg room&quot; seats.  For the other 10%, it seems a lot easier to just have Kayak give the option of a &quot;seat size penalty&quot; which each flyer can set for themselves.  If it&#x27;s a matter of getting the info, then by all means require by law that data to be given as part of the ticketing search process as well.<p>But please don&#x27;t pass legislation that prevents me from saving the $10.  I want the money, and I&#x27;m willing to sit in a smaller seat.