By the way, I noticed the power switch has been moved to the side... Is it easy to accidentally toggle the NDS Lite on or, does the lid have to be open before the switch will work?
No it's not easy to accidently hit the power trigger while playing. Don't expect it to happen. It requires a fair bit of force.
If you slide the power trigger up while the screens are still closed the DS will only boot up when you open the screens. So you wont have all your batteries drain away if for some unforseen reason the power trigger is activated while it's in your pocket/bag.