I'm sorry that Damian did not see my post in the light hearted way that was intended, even though there was a very serious side to it.
With any insurance, and I believe a PIR test can be considered as a form of insurance, the calculations must be made on the grounds of probability, not possibility. The probability of me getting drowned by a faulty roof seal is millions X millions to one. The probability of getting injured or worse whilst driving is far greater as I said in my earlier post. But these probabilities are based on statistical data of actual occurences of the problem. As Moderator Ray S asks, where is the reliable data. No one has, so far produced any statistics on this forum except for Dougie and his mouse. How many of us can say hand on heart that they have first hand knowledge of a serious problem that would have been prevented by the PIR test. My guess is very few, if any.
A few other points come to mind though. (A) If the test takes four hours, the same as a service, where are the extra staff coming from and where is the extra space for the tests to be carried out. If a workshop is busy to capacity, as many already are, how can they cope with twice the number of hours of work ?
(B) If these 'problems' exist in a caravan, why are they not designed out before manufacture begins ? It could be argued that a caravan is not fit for purpose if it is known that life threatening problems were likely due to the design. I'd sooner pay a little more for a caravan when new and have a 'safe from the start' caravan than having to shell out year on year for a test that will, hopefully, but more importantly probably, show that no problem actually does exists.
(C) Most of us have a limited budget for living generally and we have to decide where to spend that money wisely. If we are 'forced' to pay for a PIR test that immediately puts up the cost of caravanning. So what do we do, stay less nights on a site or decide to miss the annual service this year on the grounds that the caravan has only done a few thousand miles. I know which option I would spend the money on given a totally free choice, the one that already checks brakes, tyres, bearings, couplings gas etc AND electrics.
JohnM