In my 5 short years of fulltiming, I've never understood the thrill of camping in parking lots at Walmart. I have never camped in one and I don't plan on it either.
I travel on a super modest budget and folks tell me over and over I need to be camping at Walmart to save money.
DUH?

?
I still don't get it. My goal isn't to see as many parking lots as possible. No thanks. I want to see beautiful nature.
I am a fool. I budget my time and money for campgrounds and arrive before closing so as not to irritate the staff. I like to pick beautiful places to stay and many are no where near a Walmart.
Last fall I was traveling and super sick. The campground I had stayed at for several days had no more room, so I had to shuffle along. About a half hour into my trip, I realized I couldn't continue much longer. Another half hour and a A Flying J appeared on the horizon, so I pulled over. I planned to nap and try to patch myself up to locate and move to a campground. It was before 11am (yes that is morning, before noon.) Much to my surprise, the Flying J was FULL of campers who had their slides out, their steps out, several even had tables and chairs outside. I was amused to watch a couple sit outside eating their lunch while viewing the interstate. A few had blocked some of the RV parking spaces by putting their slides out, preventing me or others from parking in those RV spots. Others had taken up multiple car spaces to cram in their RV's and toads.
I was ashamed to be an RV-er and embarrassed I had pulled over at all.
A few RV-ers had parked over on the separate truck only side in spite of the numerous signs that read trucks only. Matter of fact, I think one RV-er might have upset some truckers. He parked in the middle of empty open spaces on the truck side. About 10 minutes later, I noticed two truckers pulled in on either side of him, parking ridiculously close to his RV, so close, I don't think he could have opened up his entrance door more than a few inches. Middle of the day too!
I am in an old 20 year old Class C rig, yet these folks were in very expensive new looking Class A's and fifth wheels. It makes me think some of these folks can afford the rig finance payments but can't figure out how to budget in RV parks.
For good measure, I topped up my gas tank at Flying J before parking, I would never dream of asking to stay without spending some money. I managed to back into a corner car spot that was up against a grassy trashy area and a fence, so that I was only taking up one car parking space since the 2 spare RV spaces were both blocked by slideouts in the out position.
To my right (entrance door side) was about a dozen car spaces. Within the hour, a truck pulling a 40 foot fifth wheel came in and took up 8 parking spots. I think they could have fit in 6, but they wanted the extra room of taking of 8 so that a car could not fit at either end between the lines. We are talking NOON. And the car side of the parking lot is crammed full of RV's with only a hand full of cars able to fit in.
If I were the restaurant manager, I would have been hopping mad. In my brief stay there, I saw many cars enter the lot, circle around looking for parking then leave again. After awhile the cars couldn't even circle around because an RV-er parked right down the aisle, not in any spaces at all.
I think it's a miracle Flying J puts up with this kind of foolishness but I am super grateful I was able to rest up some in view of my own illness. After my nap, I found an RV park less than an hour away that had plenty of room. It was more than my typical overnight budget, because it was a resort type place, but I was sick and needed to rest, so I paid and stayed several nights. That's what emergency funds are for, well emergencies, like getting sick on the road.
I guess you could say I am NOT boondocking at parking lots so that leaves plenty of room for everybody else who loves that. It's just not my cup of tea to go out see all the parking lots I can see.