Towing Issues: Towing from private property, car parade, tow company

Question
I was parked in an authorized parking spot in a strip center which was private property.  I had my five children and my husband with me with the intention of buying Mothers Days gifts for our moms.  When we got downtown the kids saw that there was a car parade going on and asked if they could go across the street and watch while we shop.  We parked in the parking lot and walked the kids down to the corner and across the street to make sure they were safe from traffic. This trip taking the kids to the corner probably had taken us 5 minutes.  We then returned to the strip center to shop.  An hour or so went by and I needed to take my 2 year old to the car to change his diaper before eating.  That is when I noticed my car was missing.  I located the sign at the entrance of the property with the phone number of the towing company and finally retrieved my car.  From the time of them taking the car and me retrieving it was 2 hours.  It took me an hour to find out what happened to my car and to get it back in my possession across town. We got to the parking lot at 11:15 and my car was checked in at the impound lot at 11:30. So to my best estimation as soon as I was not looking, they towed my car.  My question is, is there a time limit the car has to be on the private property for it to be towed?  I was off the property for no more than 5 minutes and I was shopping in their strip center.  How can they legally tow someone after a few minutes of being parked there if I was shopping on their property?

Answer
well depending on state law, that is the big key for how long you can be doing what they would call "unauthorized parking".  You did not mention what state you are in, so its hard to answer this part.

By your admission,  you did leave the property and the property owner - manager most likely was watching or had someone watching this... This can be a spotter or an employee of the strip mall who authorized the tow.  Or it can be a tow company that is authorized to patrol and monitor the lot for violators.

Its really bad when this happens as even a simple act of walking to the mailbox on the corner or to get a paper from a stand on the corner can open you up to being towed... This is even if you are a customer of the property you were towed from.

Now in how to battle it, well best answers would be proof including receipts with the time on them, from tenants of the shopping mall...

I know this was not a 100% answer for what you want, but in some areas there are laws which state 1 hour before you get towed, and most other places are immediate.