There's another side of stuff like this. People living up in the hills above LA near trail heads will put up fake no parking zones in front of their houses. People have gotten real tickets in fake zones.
https://www.reddit.com/r/BikeLA/comments/1pl8guj/i_started_a...
So, political vandals?
If you haven't noticed this entire thread is about illicit infrastructure. There could be a moral argument to be had (which you are not making) but no one is denying the vandalism aspect.