Well this thread just gave me a sick feeling.
For years I have had my Hypex based Marantz Ruby integrated connected to my HSU subs using both the positive and negative speaker terminals for many years. Same with REL subs.
How in the world did this not damage my amp??
Addendum: I may have found my answer. AI initially stated the Ruby had a floating ground. Re-asking the question based on output topology, it said the Ruby uses a single ended hypex module which is tied to a common ground.
Whew!!!!!!!!!

