We did this in October for our trip last week. We mailed notes to all the grandkids and the younger nieces and nephews from Disney characters telling them how excited they were to have them coming for our family reunion trip. City Hall in the Magic Kingdom did have a rubber stamp impression that they put on the envelopes. I don't remember exactly what it said but I know it was Disney World related. The postmark was Lake Buena Vista, FL. They stamped it right next to the return address.