It hasn't become a major issue yet (despite the seaplane that flipped over
on the lake a few weeks back -- i think the NTSB blamed it on a wake), but
I have witnessed some seaplanes coming uncomfortably close to powerboaters
and even kayakers. How on earth can a pilot see if there is a kayaker
where he/she intends to land??

Its hard enough to see these kayakers when you on the water (although my
trusty Furuno usually picks them up), so i don't see how a landing plane
can possibly see them.