I haven't but I think it's a great idea. It's like having one of those battery-operated emergency lights from work in your own home. The one thing I don't like about them is that they all turn on at full power. What if I'm not at home? Then that's wasted battery power that I might find handy when I do come home. If they could be set to either turn on at a low setting or turn on a small LED or something instead of only full power, that would be handy.

Actually, I have seen flashlights, like at Target, that have a permanently blinking "here-I-am" LED. That should help make it easier to find in the pitch dark. You could put a number of them in strategic locations between your bedroom and the exit and even if the power were out, you could use the blinking LED's to orient yourself and just follow them to the outside. Just an idea.

*EDIT*
Duh, if you follow the blinking light to the first flashlight, then just use that flashlight to get out. No need to follow the trail of blinking LED's. Sometimes we just make things too difficult, eh? <img src="/images/graemlins/smile.gif" alt="" />
* END EDIT*

Occasionally you'll see one of these plug-in lights that uses a flourescent lamp instead of an incandescent bulb. The flourescent would be more efficient and give more runtime or at least a broader area light. As another option, an LED bulb would be nice, too, but I have yet to see one of these emergency plug-in lights with an LED. An LED bulb would also be very efficient and give long runtime, probably much longer than a flourescent lamp.