I started doing some research on this subject because a travel friend of mine is currently dealing with credit card fraud in Panama. Internet cafes may have software that records your keystrokes as you type. In this way, when the “keylogger” sees 16 digits in a row, it knows its is likely to be a credit card number, or possibly a password if you type your password multiple times while online.
One way to combat this is to open another internet window. Then, when you are halfway through writing your credit card number or password, type some random numbers or charictures in the additional window before completeing your password.