I'm sorry but that doesn't make sense to me at all. Is that based on anything more than intuition because if not I'd like to say that mine sides with op. I'll add some numbers too. If a dishwasher has a lifetime of 20 years and a person is 'sensitive' to adds for dishwashers for a month surrounding the time it breaks, you're talking about a 1 in 240 chance if you 'randomly' target people with a dishwasher, which should be doable to predict with a 1 in 4 chance using some basic demographics. That's roughly 1 in 1000 'total', 10x better than your 1 in 10.000 ;)