As stated on their webpage, Babies R Us "will gladly accept returns on merchandise within 90 days of the original purchase date."
My in-laws bought us the travel system we registered for. They bought it right after we registered in March and gave it to me at my shower in May. A couple weeks after our baby was born in July, we decided to try out the stroller and discovered a defect. We called Babies R Us, but they could do nothing for us, even though the product was defective and even though it was from our registry. It was after 90 days. Luckily we were helped by the manufacturer, but it took a whole afternoon of phone calls.
Because most people register more than 90 days before the products will be used, this new policy is causing a lot of headaches. And remember, they will not accept returns within 90 days without a receipt unless it is from your registry. Make sure you save those gift receipts for gifts not on the registry, and don't register early for gifts you may want to return! (You'd be surprised how many gifts you end up returning!)