I think something needs to be done in the rules about setting radio sailing courses, all marks should be set so that sail numbers can be read from the control area.
At the last IOM ranking, it was chaos at some of the windward and spreader marks. Observers were shouting "contact red boat with blue boat" or "orange boat with yellow boat". Skippers were then supposed to understand who were being called. There were many unprotested and ignored incidents because reading the sail number was impossible. Many skippers missing marks, then turning back and running into starboard boats. People saying they have overlap or not when sailing away from themself at 100m distance... Its not a wonder there are arguments.
Long courses are great untill you get to the marks.
Perhaps the course setter could carry sail number cards and ask the RO if he can read the number clearly after dropping the bouy. If the course ends up being shortend, do 3 laps.
My 2p