FWIW, it uses a turbine sprung on rubber mounts, which must do pretty well by itself, but the intake path to the motor also has a circuitous route around the housing (the housing being a separate sealed package the turbine sits within, made from two pieces I think ultrasonic welded together). Foam is stuck to one side of the intake path; air doesn't flow through it directly, but particles can indeed fall off and go right into the turbine, and there are no filter elements after that point. Presumably it's circuitous to act as an acoustic muffler. The intake goes to a side vent, on which a filter element can be placed.
Yeah, they could've solved that by using, say, felt pads, or even perhaps closed-cell foam (less friable?), or different formulations (what is that then, urethane something or other? something robust and inert like PE or silicone could be used, maybe?), or adding a filter before/after the turbine to catch particles/fibers; or even just change where the restriction is (a pneumatic "shunt resistor" appears to sense airflow via differential pressure sensor), and put a filter on that (of course, as the filter loads up, resistance increases, making this a suboptimal solution).
Tim