Others (and you) note battery drain when the gps circuits are used, why does it make "zero sense" that current draw is higher when the camera is powered on, vs when it's off?

To answer your question though, yes, I have experimented several times over the nearly three years I've owned the phone (plain old iPhone 4 from sept 2010). From a full charge, airplane mode on (turn off the RF drain and minimize outside events -- namely texts and phone calls that I cannot control), phone set to sleep after 1 minute, screen brightness minimum, and with nothing else running, I can start the camera app (pre-configured to be in still photo mode, with flash set to "off"), hit the home button to drop the camera app to the "background", start and then quit the notes app to make sure the last thing I did was something other than the camera app, and doing nothing else with the phone -- lay it on the coffee table and literally do not touch it -- will drain the battery in about 3 hours, 4 max. Doing the same routine, but quitting the camera app, then starting and quitting the notes app and I can leave the phone on the coffee table for days (although I usually give up after about three and start using the phone again).

Everything else I can (and do) leave running with no ill effect.

Bug in the OS? Bug in the built in camera app? Something defective in my battery/phone? Perhaps -- I don't know, and don't really care. I just make a point to turn the camera app off when I'm done with it. Since I usually have a DSLR with me, I rarely reach for my phone for photos in the first place, so it simply isn't that big of an issue.