Exploding washing machines

There's a warning on my washing machine. It says that putting any clothing that has had oil on it -ever- is dangerous and could cause fire/explosion. And that includes cooking oil. This leaves me wondering a little bit. Am I courting disaster every time I wash clothing that's had a cooking accident? How do people who work as cooks wash their clothes? Are aprons meant to be hand washed? Or is the whole thing just meant to minimize the liability of the washing machine manufacturer?