It seems a bit hard to believe that she was putting the thong on normally, in the normal place, and this piece shot off with such force that it ended up in her eye. Did it get caught on her foot and get stretched, creating a sort of slingshot effect? If that's what happened, I certainly have sympathy for Ms. Patterson, but it's hardly Victoria's Secret's fault. It falls in the category of things so unusual that no reasonable amount of planning is going to completely prevent them.
Every other scenario I can think of was even less Victoria's Secret's fault - standing on her head in her skimpy panties and the piece fell in her eye, wearing the panties on her head, purposely stretching the panties.