Thanks for the detailed replies, folks!
I had no idea "deferrable" was even a thing.
Well, the default behavior is still surprising, I think - and it sounds like this may deviate from the standard behavior?
If so, maybe a future release could align better with the standard behavior on this point - even if this has performance implications, in my opinion, fewer surprises is better; someone could of course still optimize by using NOT DEFERRED.
I guess this would be a breaking change however?