Are HDMI cables hot swapable?

Yes, they are.

No, you have to be careful. A few of my cleints blew up the hdmi switch Please put off everything and then swap.

I would turn off my amp regardless

I accidently blew the video board on an Integra home theatre processor. It was 2 months shy of end of warranty so they covered it (I had to pay s&h both ways) but was very grateful as it would have cost over $500 otherwise. Integra was/is insistent that you unplug both units you are connecting hdmi cables to/from.

OK, seems they are not swappable. So...

I have a new cable that I want to compare to my existing cable. I have an Oppo 105 that has two outputs. So, can I just plug the new cable into the other output on the Oppo (and to a second HDMI on the TV) and then I could just switch between the inputs/outputs via remote control to see differences in the two cables?