You are in an airport. A well-dressed gentleman approaches you, introduces himself and tells you he is short of $11 to pay for a boarding charge because he has extra baggage weight. He might say: “Now they charge an extra $20 if you have more than 20 pounds. They don’t take cards at the gate and I only have $9 in cash. This is my cell number and my e-mail address, please let me pay you back”.
Of course, he will ask you for your e-mail or phone number as well. However, the phone number and the e-mail address he gives you are not his.
How to avoid: if you really believe he is out of luck, when he hands you the fake business card ask him to show you his ID as well.