I totally agree with your Ziploc bag analogy lol. If the only concern was reducing lead exposure, I bet just a plastic bag would be enough. However, if we are only talking about using the weapon and bringing it home, does storage really matter? If the particles are all over your clothes, you are just dragging that lead everywhere.

I'm thinking it's more to do with what one of the other commenters said, lack of storage suggests a certain attitude. If you're not storing it, you are probably moving it around the house, cleaning it on the table, etc. So maybe both groups of people have the same amount of lead on their weapon, but the storage group takes it straight to the gun safe instead of leaving it in their pants and letting it sprinkle heavy metal surprises around the house?