To get lost tickets replaced, you must not only have a copy of the text side of the pass, but also the receipt from when you purchased it, and the name on the receipt may be checked against your ID.
I'm not sure they will re-issue passes originally issued before 1996; at least I think that is the year when the mag stripe was added to the passes. That stripe is read by the turnstiles, and the record of pass use is in the system. The record is checked when you ask to have a pass replaced, and the new pass will only be issued with the same amount of valid time the old one still had left. The pass is re-coded with a new serial ID number, and the old number is invalidated; the turnstiles will not accept it if someone tries to use it.
I had some passes replaced last year -- DH got them out of the safe deposit box but accidentally left them in his car at the airport. The receipt and copy had never been placed in the bank, and I had them with me in the same folder as the hotel reservation.
BTW: The paper doesn't tear easily; it is tough. However, wet or creased cards will not properly pass through the machines. I find that a fishing license holder makes a perfect pass protector. These cost less than a dollar in hunting/fishing depts. at sporting goods stores and places like Walmart. It a heavy card-sized ziploc with two holes at the top for a pin or string. I put ours on shoelaces and we wore them around our necks where they were handy for FP.
They are very cool. I bought a couple for my next trip to WDW.
