Humidifiers and Martins

After 20 years of buying whatever I could afford at the time, I finally have a decent acoustic: a year-old D28.
So, naturally, I want to use a humidifier in these dry months of the year.
So, I get me a Kayser soundhole-plug type humidifier -- as seen in the Martin catalog.
So then I happen to be reading the "Care and Feeding" Martin pamphlet that comes with the guitar, and it warns against using such a humidifier; that the rubber and plastic parts of a humidifier can be harmful to the guitar's finish.
So who do I believe?

The low humidity is less harmful than sudden changes in either humidity or temperature.

I wouldn't recommend a sound-hole humidifier, for two reasons. The moisture released into the interior of the guitar will try to migrate out through the wood. That can't be good fot the finish. Then when you take the humidifier out of the sound hole, the dry air in the room starts to draw moisture out of the wood cells at the surface, faster than it can be replaced from the cells further in. That can't be good either!

Its much better to provide a steady environment, and keep the guitar tuned and set up. An acoustic guitar will 'breathe'. Once it has stabilized in a given set of conditions, it will be perfectly happy until it has to adapt to a change. Obviously, ambient conditions that are too dry or too damp aren't good, but if you are comfortable, your guitar probably is, too.

An effective way to keep a room humidified is to set up a 10 or 15 gallon aquarium, with some tropical fish. This will not only keep the humidity in the room at a healthier level for your guitar - it looks a lot better than any humidfier on the market.

Well...seeing how Martin knows a thing or two about guitars, I would tend to listen to them.
Take damn good care of that Martin.
I am on my second Martin. First one got stolen. Actually, that, my Ibanez, Marshall stacks, various effect all got stolen at the same time (after we played at this night club, we stopped at another nightclub to see some friends play, after we got out, the van and trailer were both gone :().

I got my Martin 000038 from Elderly Insturments in East Lansing, Mi. They are the largest Martin dealer on the planet. They say DO NOT use a soundhole humidifier. I also posed the same question when I toured the Martin Factory 2 years ago and the response was the same. Use a simple case humidifier. The one I have cost about $4 and has done the job.

Thanks to all for your input.

I kind of suspected the soundhole humidifier wasn't such a great idea. But Martin's inclusion of same in their accessories catalog implies an endorsement, don't you think? Maybe a call to their marketing department is in order; I'd hate to think of somebody (like me, for instance) killing a guitar out of kindness -- and ignorance.