No Overnight Parking!!!

This Walmart has no signs prohibiting overnight parking so I parked on the side where another van and a semi were parked. Later I checked and the van had left but the semi remained. Around 1am I get a knock on my door, two guys from a towing company, telling me that overnight parking at Walmart is not allowed and that Walmart had watched me through the camera and called the tow company. They asked me to leave and said they were going to tow the semi.