My answer to mini-Bics getting wet and becoming nonfunctional is to carry several when I'm in the field. Where rain or getting dunked is an issue one rides in zip-lock.

Also in my kit I carry one that has been sealed in heavy-duty foil tape. This stuff is essentially a 2" wide strip of soft aluminum with a permanent acrylic adhesive protected by a strip of plasticized paper liner. Foil tape is commonly used for assembling and sealing ducts but once you get a roll you will find a lot of uses.

The lighter is wrapped in the tinder and a bit of wax paper to keep the foil tape from sticking and placed on the sticky side of the tape after the liner has been removed. Another piece of the tape is placed over this and pressed down to eliminate as much of the air as possible. The edge is squared off with scissors eliminating any exposed stickum and the corners are rounded to prevent snagging and cuts. Sealed in this way the lighter is very well protected. I have gone swimming with mine and when checked the tinder and lighter was always bone dry.

I have, at various times and situations also carried flint rods, magnesium blocks, match safes and lifeboat matches wrapped in foil or wrapped in wax paper and dipped in wax to seal them. If you feel the need you could carry any or all of these.

I have generally moved away from these as I increasingly see them as unnecessary. But, depending on my mood and the situation, I sometimes slip in a package of four lifeboat matches that has been sealed in wax paper. This is a very compact and light little bundle. A bit slimmer than a mini-Bic. Pretty much small enough to be slipped into a jacket pocket and forgotten about until needed. Which is one of the reasons I like the mini-Bic. Cheap, compact and effective is good.

But my observation has been that usually the lighter works. When it doesn't the second source of fire does. I can't remember ever having to resort to a third. And if it came down to it I could always get primitive and spin a stick with a boot lace.