Well - the moral is to complain more, when I wrote and advocated for detection in io.js I needed people on my side - Domenic needs people to complain and help now for the browser spec - we're always a hand short :)
The standard should simply be changed to throw by default, but I guess the train has already left the station and so we're left with "bugs by design" before the spec has even been fully implemented by all vendors :(
But then again, in it's current "minimal" state of design, the Harmony Promises are inferior to any of the dedicated Promise A Plus implementations out there (e.g. Bluebird) and at least under Node there is little to no reason to use the built-in Promise object at this point in time.
http://jsfiddle.net/sb1zqjdm/ (using native promises)
And it seems that the "Pause on exceptions" debugger feature works on unhandled promise errors. Doesn't seem too bad to me.