Nope. "Contributors to Pitch In Cards may not use Best Buy Reward Zone certificates or digital coupons to add funds to a Pitch In Card."
Using a RZ Cert on a Pitch-in card is sort of a waste anyhow.
With a RZ cert you don't have to pay tax on the amount used.
Since putting in funds in a pitch-in card is the same as buying a gift card...you wouldn't be paying tax anyway.