Never got a finished neck from Warmoth and never had a problem. I prefer oil only, so they wouldn't cover it under warranty regardless. Blighty has a lot more humidity than most places in the US ('cept for the Deep South), however.
As Philly said, Teles are the exception to the "universal heel" rule. When I ordered the neck for my Criss Oliva clone, I told the guy on the phone tele heel, reverse Jackson headstock, blah blah. He was like, 'Ooo, that guitar is gonna be badass!!' PDT_008