Nor is it safe for the goon squad. If squaters start responding to such behavior by shooting on site anybody who tries to break into the building, the law will protect them because threat of bodily harm is more important than abuse of property ownership. And it should be.
Ownership of real estate implies responsibilities to the community who are inextricably tied to the geographic proximity to that real estate. Don't own more than you can maintain. Don't own more than you can use. If you have entire groups of people coming into your property and setting up shop for months at a time without your knowledge, maybe you own too much.
(Incidentally, that ethos applies to more than just squatting. The Catholic church in Philadelphia got fined a pile of money because they abandoned a church and failed to either sell it or pay the money to maintain it. It ended up with a water main break in the basement that nobody detected because nobody was on the property, and the water poured openly into the sewer system for months. The city find them for every drop of water that got wasted in that open pipe because that pipe was their responsibility; it was in their property).