I went back to the park in Santa Monica and took some pictures of the surroundings for a sign or some sorts but did not find any. Even walking around the area, I couldn't find anything regarding the park closure at 12 am - 5 am.
My friend and I both got a citation for "Park Closure" in Santa Monica and we are due in court very soon. We were on a biking trip from Orange County to Santa Monica, and had stopped at the park to rest a bit at 3:55 am not realizing the park opens up at 5 am. The police only asked a few...