They are personally liable. That's what their stamp means.
And are you claiming that insurance should not be permitted? If so, that seems... Silly. People make mistakes. If a single mistake has the potential to ruin your entire livelihood, you'll quickly find that you're lacking anyone willing to put on their stamp without putting up enough money to cover all the liability. That is, instead of them pooling together to get liability insurance, each individual will instead have to pass on those costs to their customers.
> And are you claiming that insurance should not be permitted?
I'm saying insurances should probably be limited. So there'd be some cost of doing mistakes. Ideally it wouldn't be crippling if one makes a mistake here and there, but repeated negligence would drive one out of business. I expect this would drive the price of insurance down, and the salary of the engineer up. Hopefully this evens out for the customer.
Alternatively, let the insurances cover everything, but if one makes too many mistakes (or a very serious enough one), then they would lose their right to vet designs at all.
And are you claiming that insurance should not be permitted? If so, that seems... Silly. People make mistakes. If a single mistake has the potential to ruin your entire livelihood, you'll quickly find that you're lacking anyone willing to put on their stamp without putting up enough money to cover all the liability. That is, instead of them pooling together to get liability insurance, each individual will instead have to pass on those costs to their customers.