Well, my two cents or experience, whatever you want to call it.
Over the past 20 + years, no issues. We travel all over, been up the west coast, stayed in multiple states, state and national parks, private campgrounds and rv parks, walmart, museums etc. For us, we just make sure we are aware of our surroundings, don't stay in an area that doesn't feel right. Staying for free, we go in to the establishment, ask for the manager, get permission and they usually tell you where to park, get their name and are very comfortable. We stay most anywhere, also carry maps and check websites for stopping points. Cracker Barrel, Cabelas, other restaurants, museums, even stayed the night at a gm dealership as we were getting an oil change the next day, stayed at Lowe's in California. But overall, no worries, on our part, about 6 to 8 thousand miles per year, only one time had an uncomfortable issue. That was at a campground near mount hood oregon, i woke up about 3 am, something didn't feel right, we left. no biggie. Anyhow, just go, be aware, be carful and know where you are and enjoy your travels.