A year and a half ago, we were at Epcott. I had gone to stand in a refreshment line while my wife and kids went to get fastpasses for Soarin'.
Well, a bit later, I asked for the tickets (my job was to keep our tickets in my pocket), and she handed me four fastpasses and three tickets... not four. My personal 10 day park hopper ticket (we were on day two, I think?), room key for Wilderness Lodge, and (in effect) credit card (since we had tied charging to the adult tickets) was missing.
We went back to the fastpass machines, where she figured she must have left it in the slot, but no luck. We checked with the nearby cast members, but no one had seen it or had any turned in. So I sent the family off to the Kodak section and I walked to guest services, anticipating everything from a hassle, to possible fees, to maybe even having to purchase a new ticket.
As it turns out, I had nothing to worry about. The cast members there happily cancelled my previous ticket and assured me that there was no chance of unauthorized charging due to the incident. I was issued a paper ticket good for the rest of the day, and told that my new plastic ticket/room key card would be waiting for me at the front desk of our resort that evening... which it was, of course.
The cost? Nothing but me asking "please". Disney is the best!