As far as I know,, there are NO disclosure requirements as there are for the seller of a home. If they agreed to take your trailer in trade, sight unseen, then they assumed the risk that there may be problems. Giant is the one that assumed the risk in agreeing to the transaction in that manner. As I said before, they probably low balled what they gave you for it and will most likely be able to make it up after they make the repairs and re-sell the trailer. Glad to see that Giant came out on the short end for once!