If they spent it on groceries, they were probably not getting enough money to adequately cover their food needs, and were spending time or health to cover that

If they spent it on groceries, they were probably not getting enough money to adequately cover their food needs, and were spending time or health to cover that gap. You can eat more cheaply on dried beans, but they take time to make. You can eat more cheaply on industrial fast food, but your health will suffer. Both of those impair your ability to pursue self improvement. Policing how people spend their ubi costs time and money, reducing the amount of ubi you can grant to people, and it fails when some novel need arises. There are stories of food stamps only covering half gallon or gallon sized containers of milk. So when shrinkflation shrank half gallon bottles down to 60oz, or whatever, the same product was no longer eligible. A fundamental principle of anarchy is people know locally what they need best. People know what food, clothing, and shelter they need. Trying to proscribe that only these purchases are permissible isn't something that's easy or fair, and will likely miss the needs of at least some minority communities. If lives are improving and people are getting more productive, it doesn't really matter how they spent the ubi, does it? The outcome is great, and it was efficient and bureaucracy free? Bonus.