Comment 8 for bug 30659

I disagree about handling voice+video different from voice-only calls. I'm in both cases using the computer and I think this is similar enough to the case of watching a movie (which inhibits the screensaver from starting). Note that I might not be jotting down stuff all the time and I have a very short lock timeout (1 minute) which combined with a long password means unlocking the screen actually is a significant time cost in the middle of a conversation. You could obviously say that those are silly settings, but to me as a user, I'm using the computer when sitting in front of it and talking.

About the wandering around the room for ten minutes; I have a cord about 1.5m long so it'd be a very small walk in my case.

Screen burn is mostly a problem for CRTs and then you are talking about much, much, much more time than what you'd get from sitting in a phone call. And if you're worried about that, you can always just switch on the screensaver yourself.
Same goes for laptop power consumption. (Actually, I think dimming the screen would be fine, but not turning it off or locking it.)