That's an interesting observation about what was fastest - pretty unique opportunity to train such judgment out here. Better than up in the mountains, I think. I really enjoyed the forested bits yesterday!
I noticed the tennis courts, too, but since I don't count in the results anyway and I wanted to try out some of the other possible route choices, I went run out and around (left, through the fence). Definitely slower than both other options, but interesting to check in out, anyway.
The two-tag fence in question was the ISOM fence symbol, not the thick ISSOM one, and furthermore, since it's 1:7500, I would definitely judge in favor of crossing the tennis courts being legal (even though I also went around).
I also enjoyed the forest bits, I was mad at myself for taking the boring road route twice :)