Even to discerning eyes, skimming devices aren't easy to spot. Especially when you're rushing to make a train. The MTA and the Nassau County DA's office say they have arrested four people on charges of stealing credit card information by using so-called skimming devices at LIRR stations. Thousands of credit and debit card numbers were found during the arrests. Authorities allege a married couple and two accomplices rigged nine ticket vending machines in Nassau County with scanners capable of reading card information.