There's a difference between making yourself incontinent (which is impossible unless there's physical damage) and training yourself to use a diaper without any thought (which, to some extent, is a myth all on its own).
When you first make the conscious effort to use a diaper, it may take awhile because you're being cautious, or aren't used to doing it. But over time, it is possible to dull your psychological inhibitions, sort of loosen up on your toileting reflexes, taking less thought and effort to let go.
Those of you wishing for actual incontinence, forget it. But if you're looking to let go with little to no effort, that's a different story. It's not incontinence, it's just getting adjusted to wetting/pooping without having to use the toilet.
Last week, for example, I had to run up into my room if I wanted to wet my diaper. Earlier today I wet right where I sat, in the living room, with other people around me. It just takes practice and routine to wet and/or poop without thought.