Did we ... need proof of this concept? Here's a thread just on this forum, from over a year ago, explaining exactly how to short Tether via the trade the author is "proving":
My take was this is less about proving a concept and more a nerdy/amusing/I don't mind losing money way of saying "I strongly believe Tether is a house if cards that will blow over at some point".
Hence the last line - "for the eventual pleasure of saying “I told you so”."
https://news.ycombinator.com/item?id=28796356