Correct me if I'm wrong, but they also left out the question of financing. Since UBI needs to be financed, and would require a higher budget, taxes would need to be raised. If taking on a job would then hit you with 30% instead of 10% taxes, that would disincentivize it. These tests feel a bit like testing "free energy harvesting machines" and ignoring the power chord that runs from the machine being tested to a wall socket. That's the external source of money: the rest of the country.

I'm sure we can get a perfect example of UBI in, say, Switzerland, if we make France foot the bill. People in Switzerland will be happy: taxes stay the same, but everybody has $2000 more available per month. Alas: will the French be happy?