You literally don't know what it does, though. And it's not a given that QA testing the program will lead to an answer before it leads to a bad outcome. There's an understanding, when we use software we can't read, that some humans looked at it and talked to other humans about how it works. Maybe got calls from customers about bugs, made workarounds.

If I'm just vibecoding stuff for me, and I don't understand any of it, I would not feel safe running it on my computer. And I'm not convinced a lot of people are even going to do this, because non-technical users seem to intuitively understand they are rolling dice in some way.