i dont think Li-ion are that much higher risk (than a primary), untill you add in the extreeme conditions. and even then most of the "risk" would be loosing the battery itself, and reliabilty.
the li-fe-po batts can handle conditions better than the li-ion and still be "safe" , problem is the capacity isnt so great, just depends on the need, the ability to carry and change a spare, and how screwed you would be if you ran out at inaproprite times, Because of the capacity.
and still they dont like to be fully discharged, so being in series wouldnt be so good, just Depends totally on where your light would cut-off at.
the li-fe-po is closer to the voltage of the primary, most are unprotected so there is a decrease in parts and pieces that can go wrong in rough conditions.
if it has been that long since you wondered about li-ion as the rechargable, mabey try a li-fe-po at home, and see how it works out.
if your in the middle of an actual battle, or your life is at stake, a Doller or 2 for a throwaway battery is Nothing
spend that on the first 10 bullets :laughing: and a million on the first smart bomb.
I am saying even as a great lover of rechargables, if i was going on patrol or "duty" or whatever you want to call it, i would use a good primary, even if after i got off duty i went right back to rechargable. BECAUSE , they have much more capacity, there is no cut-off on the battery itself, they are lightweight, and less total parts, less to go wrong.
Also, when it comes to good and bad, either neither or both, there can be low quality junk of any of them.