just brought this up on TM http://www.ticketmaster.com/h/lost-tickets.html
If you lost your Print-at-Home ticket you can print another copy. But if you're worried someone might find and try to use it, please contact Fan Support to get a replacement ticket with a brand-new barcode - that way only you can get in! If the paper ticket you bought online or by phone is lost, stolen, damaged, or destroyed please contact Fan Support. We'll just need your order confirmation number or the credit card used for purchase. Note: Ticketmaster tickets turn black in hot spots (direct sunlight, etc.) because we print on heat-sensitive paper - please keep your tickets cool! If you bought your lost, stolen, damaged, or destroyed ticket at a Ticketmaster retail location please return to the same location.