Do not hide the accessible version of a page
F19 is a documented failure, and it is filed against nothing else in this library, because W3C attaches it to no success criterion at all. What it breaks is the first conformance requirement, the rule about whether a page can be claimed as conforming in the first place. That makes it a stronger finding rather than a weaker one. The pattern is an alternate version that exists and cannot be found. The user is on the page that does not work, and nothing on that page tells them a version that does is available. Two near misses also fail. A page that mentions the accessible version and links to the home page fails, because the user then has to search a site they cannot use for the equivalent of the page they were on. So does a site where the route appears on some pages only, so somebody discovers there is no way across at the exact point they get stuck.
How we find it in an audit
Reviewers start on the non-conforming page, the way a search result arrives, and look for the way out. It has to be on this page, near the beginning, and it has to reach the equivalent page rather than the front door. Then we check the same thing on every non-conforming page rather than on the one we were shown. A link that exists on the home page and nowhere else is the common shape of this failure, and from the inside it looks like the problem is solved.
How affected users experience it
Somebody searches for your booking page, clicks the result, and lands on the version that cannot be operated. The accessible version exists. Nothing they can reach from where they are standing mentions it. From their side your site simply does not work, and the money and effort that went into the alternate bought them nothing, because the path they took never named it. A link to the home page is barely better. It hands them a search problem inside the site they already could not use.
Passes vs. fails
Passes
<!-- First link on the non-conforming page, pointing at the same page's alternate. -->
<a href="https://accessible.example.com/pricing">Accessible version of this page</a>Fails
<!-- accessible.example.com/pricing exists. -->
<!-- This page has never mentioned it. -->
<a href="/features">Features</a>
<a href="/pricing">Pricing</a>This guide is our interpretation of W3C technique F19: Failure of Conformance Requirement 1 due to not providing a method for the user to find the alternative conforming version of a non-conforming web page. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.