I can understand the concept of stealth in terms of safety - that those wanting to do harm may not know that someone is overnighting in the vehicle.
On the other hand, how many here would want someone living in a white van parked in front of their house? Where we live, we know and trust our neighbors. We watch out for each other. Having a transient living literally in your front yard (even for a couple of days) is not a reassuring thing. Who are they? What is their purpose? The same holds true for local police who are trying to keep neighborhoods and local businesses safe and free from wrong-doing. What are they to expect from someone "secretly" camping out where they should not be?
In the right situations, such as at an RV park, state park, local campground, or even a Walmart, this is an accceptable situation. But in a neighborhood or in a business parking lot it is not.
I agree with most of the posters here, and am not a supporter of this alleged method of camping. Gives RVing a bad name.