Nice to se a consensus of opinion from the 'pros' (but then would be surprised not too!)
I too was going to mention fish strikes, but flying fish! Worse still, had some time flying in an area where, at the wrong time of year, it wasn't uncommon to have whales 'pop' up unexpectedly; now that would really hurt (if you were flying at low level, which of course we weren't)!
Seriously, as has been said, flying at low level over water/mud flats is not to be taken lightly and is a fraught activity for the untrained. It's not for no reason that landings were the greatest cause of accidents for flying boat pilots.