I have seen those low white pipe fences for maybe 30 years. I always have viewed them as a way for the car dealership to "keep the new cars in the lot" while letting customers view them durring the off hours.Most car dealerships have one of thos white pipe fences that goes around it. Because you can step over it does not mean you are welcome there when the business is closed.
I'd be interested, if anyone that works or has worked at a car dealership has ever heard complaints or concerns from the management about potential customers looking at the cars after hours.
I am pretty sure I rember reading articles (in the 70's and 80's) explaining how to get the best price on a new car by visiting the parking lot after hours.
Your milage will vary