Usually the paperless tickets are only for premium seats (first few rows, pit, etc.) and there is a separate entrance for paperless tickets. You bring the credit card you purchased with and your ID matching the card, they should let you in if it's not yours as long as they match. They scan your credit card and print out a ticket right there. It's a little different from a regular ticket but still has the nostalgia/whatever value.
When I went to see AC/DC with the paperless ticket system I went home with a receipt. They did not print any tickets or anything remotely resembling a ticket. It was just a little credit card receipt like you would get at a convenience store.