Thank you to Paul S for pointing out a potentially uncrossable wall that could have affected route choice on the long course. We will look into that site. Competitors will note that we have acted to put a dot beside the numbers to avoid confusing 6 and on the map...we are learning all the time.
For those who did cross dangerous uncrossable walls, they are marked that way for safety reasons and myriad other reasons.
Thank you to Ja and Ju for the pix.