I came across this thread while searching for something else. While reading I noted that no one mentioned a very significant reason why boaters tend to incorrectly go "green to green" in a channel.
Most small pleasure craft (sailboats excluded) have the steering
column on the starboard side of the vessel so that the weight of the skipper
can counteract the rotational force (Moment? Torque? Voodoo?) caused by the prop. Of course, most recreational boaters do not know this fact and assume that the location of the helm
is an indicator of which "side of the road" they must adhere to.
At least this was the explanation my father gave me as a kid when teaching me to use our ski boat. Of course, all other boats on the water
were either "crazies" (if going too faster than he was) or "idiots" (if going slower).