Often as I'm working, and moving around in Max, I have found that somehow between switching views I've accidentally moved my camera, and can't get it back to where it was before. This is especially critical for cameras with animations on them. If they are moved, then the animation still play...they just get shifted to wherever the camera was accidentally moved to.
So once I've got my cameras set where I want them, I simply select all my cameras and camera targets and go over to the Hierarchy tab. If you click on Link Info, you will see a Locks rollout. Here you can lock the location of your cameras.
No more worrying about moving a camera. This is especially useful if you're using a 3D mouse.
I've also found that if you have a 3D mouse on a computer net-rendering using server, the 3D mouse can still shift your camera...strange! Locking your cameras ensures your render will come out correctly!
Apologies for not posting as much as I would like to. I've been quite busy and I'm working on several 3D projects that I might be able to share in the future :)