Cumming became an early victim of identity theft on 27 March 1888 when a man impersonating him stole goods worth 100,000 francs (equivalent to approximately £ in current terms) from a Nice jewellery shop. The thief had identified himself to the shop's owner, Mr Boxta, as "Admiral Sir Arthur Cumming" and presented a card in that name with Cumming's coat of arms printed on it. Having made a small purchase the thief requested that Boxta bring a large quantity of diamond rings, bracelets and a necklace to his rooms so that he could choose a present for his wife. Boxta was reassured by the high status neighbourhood and a pile of Bank of England notes that the thief showed him and allowed the thief to take the jewellery to an adjacent room from which he was able to escape. The thief was never caught.
