I don't have a problem with letting my baby Nago onto my neck. He only does it when I'm sitting at my computer chair with him, and he doesn't go far.
None of my others have ever tried to get onto my neck, so it isn't an issue with them.
As far as the biting thing goes, I trust Nago completely, he's never struck at anything but his dinner. On the other hand, my husbands little monster Mystic, raised himself off my hands for no reason and tried to bite my face off. It's a good thing I was holding him down far enough that he missed by at least a foot.
Gale