I would be skeptical of the idea that there would be any migratory movement amongst recipients of the benefit. The reason that the major cities suffer from vast overpopulation is the perception (whether true or not) that there are more opportunities in large cities. It also contradicts the notion that people tend to aggregate in their communities. The ability to be mobile presupposes the financial ability to do so.
On the other hand I agree that UBI would not decrease productivity. What does kill productivity is the instability of a system that makes people work without any true engagement. They stay in their jobs only because they feel they have no choice.
As someone who has actively participated in studies that attempted to apply physical theory to economics I must say: it doesn't work. Economics is people. Physics can have laws. Economic activity is human activity and is much less susceptible to the framework of exact science. It is more of a science/art.

Last edited by Ezekiel; 08/23/16 12:44 AM.
"The liberals can understand everything but people who don't understand them."
Lenny Bruce

"The cleverest of all, in my opinion, is the man who calls himself a fool at least once a month."
Dostoevsky