One rationale for the UBI is that paying it to everyone would keep it from being Welfare. It is true that if people were allowed to refuse it some poorer people would. It would be interesting to see the percentage of richer people who accepted it.
One problem with the UBI is paying for it. As it happens, I have developed an idea for a guaranteed income that would not be paid to everyone, but would be available to an unlimited number of people. (For the record, I do have an M.A. in economics.) It would be paid to retirees and adults too incapacitated to work and it would become the minimum wage/income.
The details are too extensive for this space, but are available at www.ajustsolution.com.
This proposal would make the economy more just, but it can be considered in strictly economic terms, with no reference to justice. In other words, ‘justice’ isn’t used to justify unsound economics.