Sweepstakes, Contests or instant winner games

I don't have a real good answer for you on this one. Obviously if the promotion is over, the sweepatakes material should not be distributed any longer. Perhaps the sponsor just hired a street team to distribute materials and there was some confusion on the end date.
However, I'm a bit suspicious about your daughter winning a plane ticket on an expired promotion. Sometimes unscrupulous sponsors run promotions utilizing "free" tickets that come with all kinds of restrictions, such as having to buy another ticket at full price or having to stay at a particular hotel for a specified period of time, or booking a vacation through a particular travel agency. I don't think these sponsors would be too concerned aout distributing out of date materials, so be careful about claiming the prize.