Well, I do have a slight different opinion on this topic. Although I do not store my pipes in my cigar humidor, I guess you could. The point of making humidors of ceder, is because Spanish cedar is a very dense wood, hence when the box made of this wood is humidified the wood does not absorb the moisture as a more porous wood, but the environment keeps it at the required level suitable for cigar storing. Opposite, should you not humidify your box you will find that the inside atmosphere is a very dry one. Think of it this way, do not use your 50/50 solution on your humidifier for a few months, see how low will the hygrometer indicate. I'll tell you: bone dry !!!
I remember back in the US a yard sale, I found a Spanish cedar chest - quite large, that was storing sheep's fleece. The lady said that it has been in the family for decades, and that she wanted to get rid of it since it occupied space, not even remembering what was inside. The point is, the Spanish cedar not only kept the fleece dry and mold safe, it kept the environmental humidity out, so after storing fleece for 20 odd years the thing was in impeccable shape.