We are already buying tens of billions of dollars in "free ham sandwiches" in the form of Social Security Disability fraud every year. That's a LOT of ham sandwiches - similar in cost to running a war on the far side of the planet. Extreme poverty as a result of a post-labor economy also means very high public and private costs for police, prisons, and security.
Wait a minute, are you complaining that too much money is spend on ham sandwiches? Your counterexample suggests that this money should be better spent on another war on the far side on the planet?
I'm saying that between existing welfare, existing SS fraud, and other transfer payment programs we are already spending enough that trading that for a mincome program might cost less than you think. On top of that, if the removal of disincentives to make incremental income above the mincome level are removed actually works, the net cost will be even smaller.