I know the common theme is that "Seattle would never trade up," but it honestly wouldn't shock me (not saying I expect it). We know that WR and OL are clear needs and this class has a clear top shelf of them, several of which scream "Seahawk." If you had a chance to secure the prospect you really wanted, why not make a small trade up to secure that player?
Do I expect it to happen? Of course not, but I'm certainly not willing to just write the notion off, especially if a certain OL or WR falls to pick 20, that nobody expected to.