Absolutely true what you say there. However if it works, those people using a lower cost and easier to obtain 400-550W PS at $20-$40 are going to be LAUGHING at those of us who went the $200+ PS route because someone said so, then boy won't we look silly.
Of course if the reverse is true, and it blows up lights and hubs, won't WE look like the smart ones.
The difference is "common knowledge" vs "real knowledge". If someone could explain EXACTLY and scientifically why tieing rails is bad, then I will be a believer. If someone says "dont do it because I think it might be bad", or worse "because someone else thinks it might be bad" THAT makes me want to find out the reality. My belief is that in a computer with all common ground connections and interconnections and multiple power connections GALORE, that if someone took an HDD on one rail and connected it to a common connection device that took multiple power in and got power from the other rail (like attached) that it would spontaneously combust. I would think the PS manufactureres would have thought of that possibility and made sure it was ok (boy I HOPE so!!).