A child shouldn't hide in an old refrigerator either, but it happens.. and sadly kids die.. which is why refrigerators no longer lock when closed.
It is certainly not beyond the pail that children will climb into any opening large enough for them to fit.. should they? NO... will they? A certain number of them will, no matter how good or bad of parent they have.
If you think a child can't get out of your sight and into mischief quickly, even if you are "on the ball"... you've haven't been around many kids.
I think a design change might be under consideration for commercial washing machines... much as the change to refrigerators.... I don't believe the vendor per se has liability for the child's death.. but steps should be made to ensure this doesn't happen again.
There is no way they're going to be able to design a front-loading washing machine that doesn't lock.
The machine doesn't need to be fixed. The boy does.
The issue here isn't whether kids get into mischief. The issue here is the mom suing the manufacturer.