Not at this time. A future version of siloz will allow the buyer an option to decline a high-value item, and receive a 95% refund.
Since sellers aren’t the beneficiaries of the sale’s proceeds (it goes to the silo or fundraiser), there’s little incentive to misrepresent an item. Still, exercise skepticism when purchasing items, particularly high-value items.
Sellers will never be able to back out of a sale.