I've heard that happens in the medical system. I'm immersed in it as well. I work in IT, and people will take you to the cleaners if you even temporarily lose access to data, you don't even have to lose the data. Most insurance companies won't cover an IT person, and if they do, it's 4 to 5 figures a year for the coverage.
Treadles are probably a fair bit "Safer" than the electrical machines, but I'd sure like to hear what SteveH's daughter says.