Two separate scenarios going on in this thread to my mind. Legally getting rid of renters who stop paying rent and just take up squatting is one, I understand there is bad law surrounding that , but the other is a whole different topic. If I come home from a week or two fishing trip or vacation, and someone is in my house, I certainly wouldn't wring my hands and twist about what I need to do. I don't think any man would hesitate, just as I wouldn't, to consider it a home invasion, illegal trespass and breaking and entering.
I find it hard to believe most of us here would open the door and upon seeing your home has been broke into and a home invader is present, would run back out to the car and nervously ask your bride, Oh honey, what should we do? I know I'd be swinging a bat or wielding a hand gun demanding the the fuggers to get out and make it quick.
There's a third scenario where both the owner and the renter are victims. A third party pretends to own the vacant house, draws up a lease agreement and leases it out to some unsuspecting renters. They get cash deposits, first and last month's rent and haul ass.