I've got a suspicion that there is going to be a lot of waste, regardless. There are a vast number of models, colors, and sizes. The odds that somebody else wants this specific shoe seem low.
At best, they'd need a steep discount. "You want a size 9 right Nike Pegasus in green. We will sell you that for 75% of the cost of the pair. But it turns out we have a single size 9 right Nike Pegasus in red. We'll sell you that for 50% of the pair cost."
At Nike's scale they might be able to make that work. I suspect they'll still have a lot of unsold single shoes, but they'll at least get some goodwill and positive buzz from Paralympians saying nice things about the program.
