And as for Mary Poppins...
The Chicago production had major technical issue this past Saturday. After holding the curtain for 45 minutes, they ended up canceling that evening's performance out of safety concerns. They had had some technical issues earlier in their run, but they even went on one night with the stage crew manually moving the set - which does not include the Banks' house moving up and down (it just moves upstage and downstage for the tour).
Of course, they offered refunds to the audience members as well as a chance to exchange their tickets for another upcoming performance. However, since they end their run in Chicago in two weeks, well, the seat selection is limited.