The fact that "Bomber" of Bitgrail blames some purported flaw in XRB's protocol is telling. Especially when Kucoin and Binance don't see any problems. Can't accuse him of stealing the XRB - yet. But it's reasonable to conclude that he was incompetent when it came to the exchange's funds. May or may not be criminal. But I'd say he's liable should there be a civil suit.