In what situations is it a good idea to get the other person's full legal name?

[crazyem]

other than the nice lady at the post office, whose last name doesn't really matter?

 

[SpaceAge Romantic]

Robbing a bank.

 

[crash-test-dummy]

Before they use your toilet.

 

[Wally West]

every time if you need to make a complaint you need it don't you