Dave, here lie the beauty of pipes...to a great extent you can do what you want and what works for you. People smoke pipe tobac at all different moisture levels. Personally I like mine pretty dry. Not dired out over time but freshly dried for the bowl. In this respect I personally see no reason to put your pipe in a ziplock, although you certainly can. Matter of fact I prefer to prepack my pipe and let the top 1/8" dry a little more as it makes lighting easier. And it takes quite a long time for the lower tobacco in a packed pipe to lose a lot of moisture.
