I too was impressed with the crossover holes without the danger and asked Nick about it. However, two issues with the "roundabout". First, both the short holes head in exactly the same direction and I did find it noticeable. Second, its a very awkward walk back to #7, but I realize that Dr Mac's 6th green was probably far short of the current green.
This sort of idea is used at Pennard with fairways as backstops for greens. Its not quite the same as a "safe crossover", but it keeps the routing moving smoothly.
Ciao