The Luckin Coffee scandal carries the flavor of a familiar all-American scam: a high-flying Nasdaq stock with a technology hook collapses after accounting fraud is exposed. But Luckin is a Chinese company — and that highlights a unique set of risks too often ignored by U.S. investors.  These risks will make it very hard for the out-of-luck investors to recover significant sums from Luckin, which had been taking on Starbucks in China. Luckin’s shares plunged more than 90 percent after