Towing Issues: tow from private business, walki talkies, tow companies

Question
In Las Vegas I parked in business area. There are signs on the wall "authorized Parking" but there is a wide range of area in between the stores and a self carwash where is no indication of illegal parking. I parked there last week, nothing happend. Today my car was towed. I was looking arond where a few guys with walki-talkies standing and waiting for you to come back looking for your car. The check every vehicle when you come and if you stay within the property or not. We crossed the street, they said they're watching you and if you are not back in 15 min they take your car. The rules have changed yesterday! How was I supposed to know? They drove me to the towing comp., how nice! Free shuttle! But they ask $210 cash only!
Is that legal to photograph you and monitor you while parking? Shouldn't there be signs that rules has changed?

Answer
well hate to rant a bit, but if the rules changes, how do you think that people should be notified...

The signs usually do the trick as they notify the motorists that there are parking regulations and restrictions for that area...

Now why it was towed that time instead of the others, well there are about 939330 reasons why it could happen... It could be that the property owner finally had enough of illegal parking, it could be that the tow company finally got permission to start towing.
Or it could be a result of a feud with property owners in the stores..

But the fact is that you did park there and left the lot to go to some other business and unfortunately that made it legal to tow the vehicle for trespassing and illegally parking.

Now as to the fee, well checks and credit cards can be cancelled or disputed and as such it becomes a big hassle there. Civil or in some cases criminal charges can be filed then.

Cash is the only payment that can not be cancelled and as such most all tow companies who do tows from private parking lots only take cash, due to the "customers attitudes" when they pick up the vehicle.  (now I said that because I bet you were not happy when you were there to pay for the vehicle)

Is it legal to take the pictures and monitor you and the parking lot, well I have to say that if there were pictures of you getting out of the vehicle, walking away and going into other businesses, then it would be hard to prove to a judge that you did not leave or that you were a patron of the businesses.