This seems to describe a situation where sites served over plain 'http' would pop a red 'x' or other distinguishing UI element to connote untrustworthiness.

This is almost the case already where a good number of browsers will show no positive (green indicator or lock icon) for domain validated certs - showing a preference for the much more expensive EV (Extended Validation) certs.

Screenshots of the different browser SSL level representations: https://www.expeditedssl.com/pages/visual-security-browser-s...