I'd be in favor of an opt-in thing that does it, something you get when you register with a simple explanation of why it's suggested. It could even go so far as to replace them on the fly for just you, regardless of if OP chose to use the originals or the sanitized links.
It could even suggest archive.is for those links.
or a paperclip with a face that pops up saying, "It looks like you are linking to twitter. Are you sure you wanna do that?"
Maybe not that far, Satan, but yes.
(post is archived)