The issue is whether it makes sense to post a paywall link on HN, since only a (probably small) subset of users can access it, if there is no workaround available.
EDIT: It could be argued that the upvote system would take care of that naturally (if only few users are able to access it, few would upvote it), but I can understand why it could be considered an issue.
EDIT: It could be argued that the upvote system would take care of that naturally (if only few users are able to access it, few would upvote it), but I can understand why it could be considered an issue.