alt Hacker NewsHappened to me once. I was emptying one of my child’s thermoses in the bathroom when it suddenly "exploded" and sprayed the contents all over the bathroom walls. Quite a remarkable day :)
I didn't consider it a defect, though. I can hardly imagine cheap products adopting this solution.
I would have thought they could design the screwtop so that it would relase pressure before fully disengaging the lid from the flask.