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Why not? The suggested section of an innertube for each should be easy to do. Cut from a section where it has been folded for a long time. Punch two holes a snug fit on the shackle one shackle-width apart. Thread into one of the two holes and run it up to the body of the lock with the fold wrapping it around the lock body. When you lock the lock, pass the end of the shackle through the second hole before snapping the lock closed. With gravity causing the lock to hang as it normally does, this should shed most of the water and grit. (Lock the lock when the door or gate is open too, to protect the lock from debris stirred up by the lawnmower or whatever. (This also keeps someone who is not paying attention from locking the door with you in the toolshed or wherever. :-)
No reason that the keyed alike should have any affect on the ability use this protection system.
Nor am I.
What about a propane torch from the toolbox? A lot quicker than a cigarette lighter anyway. :-) For that matter, you could probably use a cigarette lighter from the car if yours is not new enough to no longer have those included. It should be clean enough if nobody has used it for its intended purpose.
Enjoy, DoN.