'Sorry, I think I interpreted some of your comments as being overly concerned (paranoid) about it.
A regular maple neck definitely needs a finish of some kind in a humid climate (I live in a dry climate), but in any case, simply having an unfinished neck shipped to you is not going to create a problem. Once the neck is under string tension and in use, it needs protection from moisture. I believe Tru-Oil is sufficient if enough coats are applied, but it makes sense that Warmoth would not warranty such a finish since there are so many potential variables, and it is not as hard a finish as polyester or polyurethane. I'm actually surprised they would warranty nitrocellulose lacquer, but I imagine it's at least thicker than gunstock oil.