It's not my argument that competent web design is a reliable signal, only that nobody is looking for incompetent design when they're shopping for a used Camry or a new rotary sander.

When Stripe or Braintree or Paypal deliberately mess up their designs so they can signal their humanity to customers, I'll check back in with this idea. Maybe companies will start introducing dumb bugs into their code, too, because if it's too perfect everybody will know a robot wrote it.