[gigawhat]

Payday loan shops.

Don't pretend you can legislate around that problem-- if payday loans against UBI were illegal, the black market (loan sharks) would fill in the gap.

[sokoloff]

There's already a black market for WIC/EBT ("food stamps"). Replacing those with another program that would also have a black market seems less outrageous to me than supplementing them with another program with the same flaw.