I am sorry I am late. When I picked my coat up from the back of a dining room chair the high E string on a nearby guitar had managed to inveigle its way inside the slider of the front zip.
I don't think this can be explained without resorting to quantum entanglement. Classical mechanics aren't up to the job.
I tried to ease guitar and jacket apart for a while, but finally gave up and cut the string with some scissors. Until I get a replacement I will probably retune to G-D-G-B-D and entertain the neighbours with covers of The Rolling Stones' "Honky Tonk Women", "Brown Sugar" and "Start Me Up"