From the Mt. Zion website:

On April 18, 2008 the Jon & Kate Event planning committee at Mt. Zion Lutheran School was informed that, due to a change in their TV production schedule, Jon and Kate Gosselin have to cancel their trip to Colorado on May 17, 2008. We have been informed that both events scheduled in Colorado for that weekend are canceled. The event planning committee, parents, members, staff, and friends of Mt. Zion Lutheran Church and School are profoundly disappointed that this event will not occur. Much planning, time, energy, expense and excitement have already been expended in order to present this event to our community. We sincerely regret any inconvenience that this cancellation may have caused.