Im not sure people who work 90 hours have too much more or less of a risk factor of being suied over a random accident than anyone else. But I agree, winding up in 100K + of debt due to an accident is one example that is fairly rare, but we are talking about luck, luck implies chance and at the extreme ends of that the gain/loss will be extreme.
Again not saying luck is typically the dominate factor, but it is a factor and for the few people who are unlucky it can be rather devastating.