I am personally aware of three caravans that suffered the failure of the pressure regulator, which the over pressured the caravans internal pipe work, and caused £K of damage. Other professionals in the trade have also reported similar failures. As I have been at pains to say, its fairly rare, but when it happens its costly both in monetary terms and of course its usually when the caravan is in use at a holiday period so there is more than just monetary costs to consider.
As far as I am aware there is no requirement for caravanners to report all failures to you, so it' hardly surprising you may not have heard of such events. It's worth bearing in mind that your solo experience doesn't always follow trends or occurrences else where and may not match the wider experience of professionals working in the field.