Some, but very marginal.  Flash sales are an excellent tool to offload inventory during low periods, but do so sparingly – once or twice a year tops.  Consider trying them once for Black Friday over the American Thanksgiving weekend, and perhaps again during the thrifty winter months of the first quarter.  When you use them too often, however, your loyal base of customers may feel slighted for paying the regular rates.  Moreover, you’ll change consumer expectations.  They’ll wait for the sales periods and only buy at those discounted rates, eroding your REVPAR over the long-term.  If you find yourself relying on flash sales to maintain an adequate occupancy, start to look for the underlying issues.  Access your property’s guest services and marketing strategies – something much more fundamental than your slate of promotions is hampering you from attaining a steady stream of reservations.