There was once a kosher establishment cooking a pot of 60 hot dogs. Suddenly, a non kosher hot dog fell into the pot, and the mashgiach just served them all!!
[end sarcasm]
Come on, people. Anecdotal evidence does NOT equal halachic problem. There is a certain halachic degree of certainty which is necessary to be halachicly confident in a food’s kashrus status. That is ALL that is needed. Period. For all of these stories, there are many thousands in which everything went fine. If according to halacha the chance of problems arising is too remote to be ???? for, there is no problem. Until you know the intricate halachos of when we are and are not ????, such stories are simply fear-mongering and appealing to people’s emotions. The Liberals would be proud.
[Clarification: Yes, I do know the difference between bitul and other areas of halacha. I was just trying to make a point.]