You're not describing a position taken by sane libertarians, though. Their argument is different: that if the government didn't regulate so much, customers would depend on the merchant's reputation, possibly backed by independent testing done by private sector institutions. A modern-day parallel would be electrical safety. In the US, this is largely handled by private organizations such as the UL. You can buy a non-UL extension cord or a toaster if you want.

And look, I'm not arguing that this is a better solution. But I think it makes sense to attack the strongest version of that argument, not the weakest one.