Well... A year or so back the homeless in Colorado Springs were living in an open area down across from the interstate in tents and locals called it "tent city". They were held up there and their community grew and grew and grew until eventually people driving down the interstate could see the tents and people started complaining that the area was an eye sore and people didn't want their community represented that way to tourists and those who were passing through the city... so the city evicted the homeless from this area in the end... but until they did they were fine and were accumulating there for a while. It wasn't until tent city started to take on its own neighborhood look that it was really noticed and frowned upon.
I have come across plenty of homeless taking up residence in old deralict train tunnels and along the river courses and the city, the police and pretty much anyone else never bothers them or tries to run them off.
I was friends with a girl who was homeless and living out of a tent at the top of Garden of the Gods for 3 or 4 months.
I even met a homeless man who was left alone living at the back end of an old overgrown unused football field under the old bleachers.
I wouldn't really consider taking up a mock bug out base camp in an old factory or old power plant unless you first spoke to the city and the owners of the property because if it is property, someone own it or oversees it. That is pretty much a safe bet.
I really don't know what locations would or wouldn't go unnoticed for someone to be taking up even a mock residence in in or around larger cities but if you really want to find yourself a location to do a mock bug out in or even plan on being a stop on a real bug out situation or something like that... then look around your city and find your homeless folks. They know every nook and cranny in your city and can point you in the right direction of places to go where you aren't likely to be thrown in jail for setting up camp for a night or two.
Don't be afraid of talking to the homeless... sometimes lol... not all of them are going to take a hit of bath salts and try to eat your face off.
While a lot of them are mentally unstable, mostly because they cannot afford the medication they need to maintain a semi-stable state of mind, (schizophrenia, bi=polar disorder, depression) there are a lot who have no mental illness, they just happen to be down on their luck because of circumstance. Some even choose that lifestyle because they dont want dependance on material wealth or whatever reason they have.
The girl who lived in a tent atop garden of the gods chose to be homeless rather than bow down to her mother and live with her oppressive rules while she got back on her feet after losing her only source of income. And with the job market being poor for her skillset at that time, she actively chose homelessness. Though she still worked for a temp agency. She was a college graduate and the other problem she faced was the fact that she was from Alabama and that is where most of her family was. She didn't want to leave colorado.
SO you see... it isn't going to hurt you to chat with a homeless person and they can give you the best direction to the places you yourself are seeking for yoru specific needs.
Look into it.


