Rails is a popular framework and supports an optional "data-method" parameter, like this:
<a rel="nofollow" data-method="delete" href="/en/logout">
It would be very bad to automatically follow such links if data-method exists and is not GET.
Solution: Simply don't preload a links that have a data-method and provide a value other than GET (any case).
See also: instantpage/instant.page#47