BTW, I've sometimes wished for a mode where queries would silently have result ordering intentionally futzed, to eliminate any possibility of dependence on tuple ordering (as well as having sequences start at some random value). I guess with the hooks that are in place today it wouldn't be hard to stick a ORDER BY random() in if there wasn't already a Sort node at the top level...
+1 In Oracle, we sorta had that feature by adding a parallel hint to a query even if it didn't need it. It came in handy.
