With UBI, there is no means testing. So the main “abuse” possible is income tax evasion.
It is possible that there would be fraud around pretending to be a person when that person doesn’t exist, or continuing to collect benefits for someone who is dead.
But “are you a live person” is much harder to fake than “did you make sure you didn’t do these 6 illegible things that would make you ineligible”.
Again, we're not talking about UBI money, we're talking about money earned after UBI. Without UBI, people who work in cash businesses have to report a certain amount of income to justify their living expenses. With UBI, there is nothing to justify, and it makes it much easier to operate your own cash-only side hustles tax-free as long as you live in a place you can afford solely using UBI.
> You will still need the bureaucracy there to be monitoring for abuse
When you eliminate means-testing in favor of income taxes and eliminste the myriad different definitions of income and assets for qualification for different programs and the opportunity it creates (and the incentive funding cliffs create) for specialized benefit fraud, there is no special “UBI abuse” to monitor for. You have to monitor for tax fraud, but we’ve got a bureaucracy doing that at society-wide scale anyway.
It is possible that there would be fraud around pretending to be a person when that person doesn’t exist, or continuing to collect benefits for someone who is dead.
But “are you a live person” is much harder to fake than “did you make sure you didn’t do these 6 illegible things that would make you ineligible”.