The most frequent damage to a WDW ticket aside from demagnitizing it, is running it through the washer (or the Lazy River!). I bet more tickets are replaced for that reason than anything else! Since, when they are washed, they won't scan, and most of the time, it washes off the letters and numbers used to replace it, please save your receipts or make copies of the tickets and bring them with you. With the new MYW tics, it will be much easier to look them up and replace them, because each ticket will belong to a particular person and all of the information will be in the WDW ticket data base, so as long as you have your ID, you are golden!