Don, I can understand your point, but that still doesn't make the case for giving away the negatives as opposed to destroying them. If she has no plans to reprint the negs, then she has no need for them, and if she does have plans to reprint the negs, she has no right to them.

Shredding protects all parties equally and should satisfy the legitimate "reputation" concerns on both sides (i.e., the reputation of the photographer as someone who produces quality work and the reputation of the model as a person of modesty, if that is a personal concern).