On my map, the circles for controls 12 and 13 are both cut, in both cases to avoid obscuring a distinct tree. So it seems the planner for today's event can cut control circles. Did he/she not do the same on the Brown course?
Well those are the only 2 that are cut - a quick look shows:
Thicket on S edge of 227 (#18, final control)
Another knoll on NE edge of 206 (#15, knoll)
Obscured path towards 206 (#12)
all potentially quite useful detail...