I was at a dealership and at handover, they were highlighting the "remote" possibility of the leaking bellows and instructing the customer to take to any VW dealership asap should water ingress occur.
I would insist on a water test at handover.
Interestingly, do you know when your Cali was built? There is a suggestion, again on the German board, that all Calis entering build after July 1st were fitted with the "C" bellows version. I'm not sure there are as yet any concrete examples of later models leaking but that may just be timing of the builds.