OK, but then what? Leave the LED on for 24 hours after you've captured a single frame? At that point the LED isn't really indicating camera usage because you'll just get used to seeing it on all the time whether the camera is in use or not.

A ranfom thought, that probably won't cover all cases: a second LED or a colour LED. One LED/colour indicates the camera is active, the second can be on for a longer period of time (and perhaps dim as time goes on). I prefer the second LED option since it is better for us colourblind folks, though I suspect there would be more resistance to the idea.

And, of course, covers are an option.