Hi chew socks,
I looked through your posting history and see you've asked some good questions and gotten some good answers on lithium-ion cells. I think unprotected cells are fine if you've taken the time to really research them and learned the proper way to care for and use them.
At a very minimum, I would say read and understand all of what mdocod has posted here:
MD's Lithium-Ion>Incandescent Guide
And there is a lot of good information here as well:
BatteryUniversity
Your main goal with unprotected cells will be to keep them from over-discharging. If one does happen to get over-discharged, please don't stick it on a charger and try to recover it.
If you feel comfortable with the risks, and feel well enough informed to use them safely, then go right ahead. If you feel uncomfortable with using them, then there really is no amount of cost savings that can justify compromising your safety and well-being. Spring for some protected AW cells and enjoy your lights. But it's still a good idea to read MD's guide even if you're going to use protected cells.
Personally, I started out with NiMH cells and a good charger for them. I figure I can get plenty of great lights that run on that chemistry while I'm learning more about lithium rechargeables. Also, the more I use my more-forgiving NiMHs the more I'm getting into the habit of thinking about the batteries -- what is the charge state on this cell; when should I charge this one; how long have those batteries been on the charger; what is the approximate time they should be terminating; etc.
