I suppose if you happened to have forgotten to have brought your umbrella;
you just happened to be wearing a large scarf;
you did not mind ruining that silk scarf;
or looking more foolish than using your kelly/birkin plastic bag (if using one of those type bags);
and you bag would take a few drops (as silk is not impervious to rain).
Improbable at best. But fun to look at -- thanks CandyCouture.