Even Elon could lose his credit card or something, the story they spin is always something like that "I am rich but in a pickle, please send some money here and then I'll send you back 10x as much tomorrow when I get back to my account", but of course they never send it back.

Edit: But of course Elon would call someone he knows rather than a stranger, rich people know a lot of people so of course they would never contact you about this.