I think that it is extremley naive to expect all alutech vans to not have any water ingress. A minor drop off in quality during build could lead to a leak on just one or a number of vans. What the Alutech vans do have is more resistance to water ingress causing damage than the traditional van materials and construction gives. So even if you do have a leak it should do less damage than in a traditional van, and repair techniques are such that I really do doubt that any future trade in will be adversely affected providing the repair agent does a satisfactory job.
It would be nice to live in a perfect world where nothing ever goes wrong but life is not like that. My Bailey has a new front end and new back end both replaced because the original production technique led to panel cracking and water ingress. Both we spotted duriing service and my dealer repaired them at my convenience which had no affect on our holidays and planned breaks. So yes it was disappointing but both Bailey and the Dealer gave excellent service.
It would be nice to live in a perfect world where nothing ever goes wrong but life is not like that. My Bailey has a new front end and new back end both replaced because the original production technique led to panel cracking and water ingress. Both we spotted duriing service and my dealer repaired them at my convenience which had no affect on our holidays and planned breaks. So yes it was disappointing but both Bailey and the Dealer gave excellent service.