We'll, I guess shopping costs money and depending on what it was and what it cost she may have felt perfectly justified in getting her shopping back.
Still a daft thing to do though!
One would have to place little value in ones life to make that decision. Life is cheap I guess.
Once when I was cycling home from the bike shop I cycled over a level crossing and the bump as I went over the rails caused the pannier to come off and onto the track. I heard it fall off so I stopped and went back to the crossing, seeing it lying in between the rails on the Horsham bound track. Sods law dictates as soon as I reached the crossing the lights started flashing followed by the barriers coming down. Theoretically there was a good chance I could have dashed onto the crossing, grabbed the pannier and got off well before a train arrived (it can be a good 30 seconds between the barriers lowering and the train arriving), but I decided it wasn't worth it and waited. Luckily for me the train that went through was Crawley bound so my pannier survived intact and I could retrieve it when the barriers raised and before traffic started moving.