It absolutely irritates the crap out of me that vehicle glass repairers, many bodyshops and ham-fisted DIY'ers do not know or do not care about the significance of these membranes on car doors. In a wet climate like ours they are essential for preventing water ingress. Most people don't realise that car doors with slide-opening lowering windows are designed to allow moisture to run through them.
The number of times I have seen these torn, patched up with (paper based) masking tape or simply missing shocks me. Wet carpets and rusty floors are the direct result.
Incidentally, the best stuff I have found for re-attaching these is the rolls of mastic used for semi-permanently attaching tile-to-bathtub trims The mastic is a thin (4mm) strip and sandwiched between two layers of waxed paper. Sticks brilliantly to metal and the membranes.