I agree with Ron, a bad cabinet is just that, a bad cabinet.
What we need to realize here folks is that in a way, we're talking out of both sides of our mouths, meaning:
A) we're wanting cabinets to hold their shape, form and joints while using the same cabinet to hold moisture. In most cases, wood in general is not made to do this or do this well.
B) we're talking about 70-65% humidity, which for a lot of us, is LOWER than what we have in humidity levels outside our homes for much or all of the year.
C) The amount of humidity we're talking about is not excessive. In most situations, for those of us that keep our humidors at or near 65%, you could leave your damn cigars sit in a end table drawer...if you lived in FL or the likes, hell, even WI in the summer.
That being said, does your other furniture in your home get all warped and bent out of shape during the changing of the seasons? If so, look at that furniture, in most cases the stuff that does get all bent is most likely not the greatest furniture to begin with and has moderate at best joinery. A well made cabinet will hold it's shape well over the decades if it has great joinery. If you get/have/acquire a poorly made cabinet, really the only thing you could do is install a moisture barrier between the inside of the cabinet and whatever you line it with to hold moisture away from the cabinet.
Otherwise like Ron said above, "if the cabinet is built bad, it can still leak or warp."
