In the last few weeks, there was an uproar regarding two Chinese Cultural (Jade) Relics up for auction by Bonhams, believed to be stolen by the Anglo-French forces in 1860 from the Beijing Old Summer Palace, also known as Yuanmingyuan. Seems like the owner has requested to withdraw the two jade pieces to avoid further backlash.
Difficult to sell in future? I doubt so. China to fight for the return of the cultural relics? Tough.
With the backlash (or marketing), Chinese buyers/patriots can perhaps approach the owner privately to work something out, and probably avoid the buyer/seller premiums at auctions.
More details can be found at:
http://politics.gmw.cn/2012-10/26/content_5486777.htm (in Mandarin)