The key here is that it would have to truly be "en masse." Not just a few dozen people, or even a few hundred. Millions. All at the same time. Problem there is good luck convincing that many people to do it. Everybody's so scared, so programmed and conditioned. They have too much to lose. Try convincing somebody who's got several kids that they should do this...and let's face it, most people have kids. They won't, solely because of the kids. So then that leaves only the non-kids people. Young singles, young couples, middle aged people whose kids are out of the house, and retired people.
Middle aged people are concerned about their impending retirement and golden years...so, too much too lose. The loss of security isn't going to be worth it to most of them. The idea of being in one's 60's or 70s with no place to live or money to take care of their needs...no insurance, no meds, living in such an unstable crazy way after a lifetime of stable security. Bad idea for them. Then retired people...they're already in the middle of that, so, not going to throw it away.
So that basically leaves young childless people. Are there enough out there? I don't know.
Zero One wrote:-Refusing to pay any form of rent or taxation
-Declaring your home to be yours and effectively 'squat' the premises, possession being 9/10 of the law
-Asserting your basic human right to shelter and accomodation
Back during 1995-1996, I needed a place to stay and so wound up crashing on my friend Mike's floor. After I get there and get settled in, he reveals to me that, Oh, by the way, we're living here illegally. 
This house was a re-possessed house that we took over. We still pay rent, but we pay it to this guy named Henry who finds the houses for us. Eventually we'll probably get kicked out by the cops, so we just stay as long as we can. Is that alright?
I listened, like, "!!!" Wow! Cool. Sure. Shrug. I mean, I was just about to turn 21, and my life was a circus. So sure, bring it on! 
I just saw it as a fun adventure, like everything else that had been happening to me over the past few years.
Turns out that the lead rooommate guy (steve, later wound up becoming my boyfriend) was into researching Don't pay taxes, Don't have a driver's license or registration, Don't have a social security card, the United States is a corporation, we've been hoodwinked, etc. You know, that whole deal that was mentioned on the FBI brochure that morningsun76 posted in his Driver's Licenses thread. This guy was one of THOSE people. His phone was tapped later on because of it, and his sister was dating a former Special Forces guy who also was way into that, and wanted to move up to Oregon or Washington and go be part of some survivalist militia group. (he became crazy and abusive and she gave him the heave ho.) But anyway, so yeah, I had first hand experience with what it is to be involved with that supposed "possession is 9/10 of the law" and illegal squatting and what you outline here. It sounds well and good and you can spout it til the cows come home, having the memorized speeches (as also mentioned in that FBI brochure ) but trust me...the cops eventually come to kick in your door. They don't care. What happens is they start posting notices on the door, giving you the deadline date of when you have to be out, letting you know that if you're not out on your own accord by that date, they will come in and force you out. They also start flagrantly poking around the premises. They'll try to open the windows on the ground level and open any doors. So doors always have to be locked, 24/7 and all ground floor windows closed and locked as well. I have an interesting story about this one night the roommates were all heading out the door to go somewhere, but I wasn't going with them, so I just jumped in the shower, getting ready to settle in and park myself in front of the word processor and write all night. The roommates got as far as the car they were going to use when all of them just stopped and looked at each other. They were all overcome with bad feelings that something was really wrong....don't go. One of them, a girl (will call her "D") was the first one to say something. Mike and Steve agreed that yeah, they felt it too. Something is wrong. Don't go. So all three just turned and trotted back inside, closed and locked the door and basically, just sat down in the kitchen. Waiting. For what, they didn't know, but, they sat there anyway. Meanwhile, I'm in the shower, totally oblivious, and as I'm getting out of the shower I start to hear banging and pounding going on outside. Somebody is angrily pounding on the front door, being crazy. I hurry and get dressed, like, "oh shit!!" and get out of the bathroom. I see the doorknob jiggling, obviously locked with someone trying to get in. I go into the kitchen and find the roommates gathered around.....and both guys have a samurai sword in their hands, just waiting. "I thought you were going out?" I said. "We were." And they explained what happened. The banging was a cop who had shown up and was determined to get in. He was jiggling the doorknob, kicking and pounding on the door, and roaming all around the premises trying to get in. And like a cop, he was there for probably a good 20 minutes. Cops will take their baton and just repeatedly bash on the door, over and over and over and over. They figure you'll get scared and intimidated enough to open it.
Had the roommates not been overcome with that bad feeling, they would have left to go out, leaving the front door unlocked, with me inside, in the shower, with the bathroom door unlocked as well. (Defenses slip...laziness happens....you start to think, Oh, nobody's come around in weeks, it's safe, you don't have to lock up......X!) And yeah, that angry cop would have been barging right in on me, in the shower, as I was home alone. 
Not good. He would have shown up only MINUTES after they had taken off. AMAZING timing, huh? Yes, let's hear it for the matrix. But let's also hear it for the good guys who intervene. 
But yeah, that's just one anecdote of the sort of thing one has to contend with when they embark on this sort of thing. I mean, I think maybe it could be done, but again, it would have to be seriously "en masse." Possession is 9/10 of the law doesn't fly. They don't care. They're going by a new set of rules now in this country, but the public isn't being informed.
"Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "Holy shit ... what a ride!" - Anonymous
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"I get by with a little help from my (higher density) friends."
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