Okay, that's not quite what Johnny Cochran said, but it applies here….
I was picking up some foam for a non-bike project, and the price was good so I got a little extra. But then it wouldn't fit into my pannier, at least not without more folding and squashing than I felt up to there on Maple Street downtown.
At first I considered putting my arms through the bag loops as if it were a knapsack…but the weather was too warm for that sort of thing.
Then I looked down and saw that I could just cross the loops bandolier-style on my saddle and let the bag itself rest on the luggage rack. After all, it needed to last only seven miles.
The material is thin (and will be recycled, by the way), so it was perfectly comfortable, and the package arrived at home undamaged. Could easily have lasted twenty miles.
Looked stupid, but I didn't care. It got the job done!