Battery tube: non conductive inside, metal on the outside; kaboom, or safe?

Theoretically speaking (before practice would be applied), if one were to make a narrowing battery tube for a 6P into which AA rather than CR123A primaries were inserted, and the inside wall of the tube (in which the batteries sit) was composed of something non-conductive (plastic, pvc tube, cardboard, wood), and the outside wall of the tube (which touches the original inner walls of the flashlight body) was made of something conductive, but didn't touch the any part of the head, emitter, or battery contacts...

...would that be problematic?

Picture (as an overlarge example) a cardboard toilet paper roll with batteries inside of it, and the outside wrapped in aluminum or some other metallic or conductive foil, but the foil doesn't fully extend to either end of the outside of the cardboard tube.

This is a weird, theoretical question, but please help me satisfy my curiosity.

I have no clue why you'd make such a composite tube, but unless I seriously misunderstand the construction of the 6P, there's nothing there for it to short out.

Am I misunderstanding something? It seems too obvious...

There would be no problems except cost and threading the ends.

Nope, no misunderstandings. An admittedly strange, but theoretical question, basically wondering about the risk of short circuiting things; now that I think about it more, though, it makes sense that it wouldn't be a problem - the inside walls of the body are metal, anyway, so metal touching them and a non conductive tube would be...well, like there's no difference at all.

Thanks for considering this bizarre question!

Wouldn't the metal body tube be necessary to complete the circuit? From what you are saying, it seems to me like the metal part of the tube (let me know if this is wrong) would not be touching the rim of the tailcap, which would break the circuit and cause the light to not work.
In your foil analogy, you state that the foil would not extend to either end of the tube, which wouldn't work, since it wouldn't touch the tailcap.

However, just taking a stock tube and putting a plastic spacer cylinder in it should work, but you would not be able to fit 2 AA's in the same space as 2 CR123's, and the voltage would be lower.