B of A told me to always tug on the card readers at fuel pumps. If it comes off, it has an illegal reader.
My debit card comes out at Sam's because they don't accept Visa, a bank ATM and Walmart only. Chase changed from MasterCard to Visa due to Visa using the chips. Walmart is using chip readers, but I haven't run across anyone else. Chip readers are more widely used in Canada.