Since the money you make on your rookie contract is slotted, I'm not too sure how big a deal a player, fresh out of college, would have with being moved to Safety.
Hunter did, of course, but that was after awhile in the league, and as a late round choice. I'm not sure he got the money he thought he should after logging some decent playing time. If he assumed that he would be cut/traded soon, maybe it made sense for him to get more experience at CB, the higher paying position in Free Agency, then Safety.
Not that it really matters; was a dumb move on his part anyway.
I guess what I'm saying, is that a rookie picked in the first day shouldn't worry about that too much. A Safety will get paid same as a Cornerback in terms of draft slotting, and that player can always try to get paid as a Cornerback when he enters Free Agency for the first time.