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.
You certainly can, but you can't tell people anything about how it works, if it's safe, whether it spies on people, when it needs to be upgraded, etc. Is there going to be a market for vibe coders who sell services they don't understand? I don't know.
For documenting business logic, code is highly specific and dependable even with non-deterministic compilers. We can look at code and say "Yes, we can connect this to our Stripe account, because we have reviewed what it actually does." We can mock services and test that it works. We can do all of that without reading build output
The same, obviously, cannot be said of LLM prompts. And due to the flaws (and strengths!) of Natural Language, I'm not sure that will change. If someone told me their vibe coded app was safe because they politely asked it to be, I obviously wouldn't use their service. If they told me they asked it to write tests and do mocks, I wouldn't know if it actually did. A pure vibecoder can, at best, reread the prompt they gave, and maybe ask the LLM if there are vulnerabilities, hoping that it finds something.
Maybe we will get to a point where people are feeding 80 page specifications to LLMs as the input, but I'm not sure a person who is capable of writing that level of detail but incapable of learning to read code really exists. I don't think it will get that far. I think people will keep their prompts short and just roll the dice, QA testing.