I understand your logic completely. In theory, yes its a good idea. In practice it can create more problems than it solves, like the flooding of the airboot. It would also be a good idea to connect the vents to the boot at multiple points to avoid blockage, same as routing one pair of the line up high and one low. This would mean an airboot full of holes and hoses. Just more complicated. In practice, if the filter is that dirty, it should be changed as soon as possible to avoid drawing dirt through it.