I was under the impression that HDMI was built to be hot-swap ready, like a USB device. I was told recently that unplugging HDMI while devices were powered on was risky and could actually cause hardware damage.
Sure enough, my PS3 manual states that you must turn off and completely unplug both the TV and PS3 before connecting/disconnecting the HDMI cable. Same instructions in my digital camera's manual.
Is this really necessary to completely unplug devices from the mains, or are they just covering their butts?
Turning the power off is easy enough, but it would be a huge hassle to unplug my wall mounted TV just to connect my camera for a slideshow.