iMac G5 and constantly powered FireWire ports

First a report from Francis:

At the end of august, I bought an iMacG5 2GHz 20". I quickly realized that unlike my previous iMacG5 1.8GHz, the FireWire ports remained powered while the iMac was turned off.
I called Apple Support and they immediately told me that my brand new iMac was defect, and I quickly received a new one as replacement.
But with the new model the FireWire ports remained powered too...
So, a new call to Apple Support, and this time they told me that it was normal!! The FireWire ports of the new iMcG5 models remain powered even though the computer is switched off.
So now, I have an iMacG5 with an iSight and an external HD constantly turned on.
I do not know what to think about, when I know that I have a iMacG5 at work also bought at the end of August, but unlike mine at home, this one when it is turned off also switch off all peripherals...
Where is the truth...

Already with the Mac mini, the FireWire port is constantly powered, making all peripherals plugged into it unable to enter sleep-mode. It is still unclear if this is the new Apple way to NOT contribute to energy saving politic or rather a firmware bug, but it would be nice to have a clear statement from their side.