Given that human wants are infinite, why would someone with no job but a basic income not commit crimes to increase their income? They have plenty of time on their hands, and their social status would be a function of how much wealth they had beyond their basic income.
If I get a $270 check from the government every week (14K/year), what incentive do I have robbing a gas station, which will probably have less than half my weekly pay in the till (unless of course I carefully time my robbery).
It would be like a developer who makes ~$85K/year breaking into someones bank account online and transferring just $800 out. And consider the punishment of that crime versus armed robbery.
What you would likely see is people collecting wages off the books. People working odd jobs part time for maybe $250 a week and collecting their minimum income. Way less risk than crime; much better pay. This is bad, but nowhere near as bad as robbery or working the black market.
I doubt people who rob gas stations post often on the HN. But consider this: it takes money to vandalize as the spray paint does not grow on trees and even when you stole it you are missing an opportunity to steal something you could pawn/sell (like washing detergent or booze). Yet the vandalism does not stop.
Spray paint graffiti generally isn't used by independent criminals. It's usually gang related. Or used by an artist (But they'd spring for the good stuff, and aren't really doing any harm).
You can get spray paint for $1 at the dollar store. It's crap, but it's not like you're using to rust-proof your patio furniture. You can even get "used" cans at some places (like pawn shops). Considering the age restriction on purchasing it, I'm guessing either A) people turn a blind eye to that rule B) it gets shoplifted, or C) Old gang member member buys and distributes it.
Gangs use graffiti to mark territory and presence. They don't necessarily steal it. The person writing it is designated to write it. Overall, they don't use much paint and probably don't care about paint quality.
Artistic tagging and graffiti are a different thing. Due to the amount of paint used, they do tend to steal it if they lack money. "Racking" or stealing it is also considered a part of that outlaw culture. A large mural can cost hundreds of dollars to execute. Even a small picture can take a few cans of paint.
To get an idea of the amount of paint, search for images of "gang graffiti", and then for "graffiti murals".
My point is this: people are, essentially, paid not to vandalize. Don't buy paint and pocket that money for being a good citizen. Yet they go and do it anyways.
The idea that they will suddenly change their lifestyle after being given some unconditional stipend seems to be in a direct contradiction with the observable behavior of vandals.
The marginal value of money decreases as income goes up. So a crime that has an expected positive return when you have no money becomes less and less worth it as you become richer.
I would think people with basic income would be much less likely to commit crimes because a) essential needs can be met and b) they would have something to lose (freedom, time, money).
Beyond that, there's something inherently silly about your question - perhaps its the way it assumes the worst of people. You might as well ask why don't teachers get tenure and leave as much teaching as they can to subs without being fired, or why don't programmers pass all their work on to elance or odesk and get some additional outside work to make more money. These things may happen on occasion, but I'm inclined to believe that most are not so mercenary/sociopathic.
