Too funny. It really didn't matter at the time. Heck she could have refolded more easily at home rather than take the time and space to fold them on the bias there ... at a picnic! At a picnic I would think getting them away from any food or hands with food would be the most important thing.
I agree she is now officially a member of the Quilt Police ... and most of them are rude.
I laughed because she used plastic bags.
However, that said I have been told for years now that folding on the bias does have less strain on the fibers. Since I don't have much room mine are folded in my display case ... on the bias. Oh to have the space for an extra bed to put them all on.
ali