Or, perhaps more reasonably, HN could include a little warning symbol/message next to any link that isn't served over TLS. It could also prompt the submitter a

Or, perhaps more reasonably, HN could include a little warning symbol/message next to any link that isn't served over TLS. It could also prompt the submitter at the time of posting if they specify a URL that starts "http://" http://" giving them the opportunity to change it to "https://" https://".