Ahh that old gem.
I have actually done this before and it can work quite well.
Simply ask them "How do you spell your name?" (So u can add them on facey or on your cell phone or whatever other good enough excuse you can come up with at the time)
Ofcourse this is not 100% fail-safe.
For instance:
ME: "How do you spell your name again, I'll add you on facebook."
OLDER MAN: "It's spelt J-I-M, you know, Jim"
OLDER MAN: "you forgot my name didn't you"
ME: ".....yes"
Chat with our AI personalities