Warmoth's info on
this page explains their position well.
Here's the relevant bit:
All our necks are dipped in an oil based penetrating sealer which is compatible with virtually all secondary finishes. This provides enhanced stability; however, it is not adequate protection for playing. We strongly recommend you apply a hard finish to all non-roasted Maple, Mahogany, Walnut, Korina, and Koa necks. Oils do not validate our warranty requirements. We understand the attraction of raw or lightly oiled necks. They feel fast and are not sticky. Unfortunately, they are much more susceptible to moisture related warping and twisting. Our experience is that hard finished necks seldom warp. Raw or oiled necks don't fare as well. About 10% are rendered useless from the torture. The more acidic your perspiration, the higher the odds are against you.
If you must play a raw neck, that's cool; it's ok. A neck is just a tool. Just be aware of the risk.
For a valid warranty, a hard finish must be sufficiently thick to completely cover the wood. That means no wood is exposed and you are actually playing on the finish, not the wood. Now, it does not matter to us who applies the finish. Of course we would love to do the finish for you, but if you choose to do it yourself or have it done elsewhere the warranty is still valid.
We provide a 2 year warranty on all necks finished by us at the time of order.
We provide a 1 year warranty on all necks properly finished by a third party.
