[Chris is me]

Originally Posted by GeeTwo

Pneumatic (leaving out descriptions of people) generally means "containing or working by compressed air". The game manual expressly excludes (via R77L) pneumatic tires (which usually do not do work beyond acting as springs), vacuum-producing devices (which can be argued as non-pneumatic according to the general definition as they work on the difference between ambient and rarefied air), and closed-loop shocks (which act as springs) as pneumatic devices. It does not expressly exclude fans, radial flow pumps, axial flow pumps, gravity pumps, or impedance pumps. If any of these devices create compressed air that does work (and there is no minimum PSI limit defined by the GDC for compressed air), then by the normal definition of pneumatic in the English language, I consider them to be pneumatic devices -- until and unless the GDC rules otherwise.

You're not really addressing the points people are bringing up here - "compressed air that does work" isn't really being created here. Air isn't being compressed - it's flowing. This air is pushing outward as it is flowing through a somewhat constricted opening, but it is not really being compressed. If you are really saying "there is no minimum PSI limit" and that literally any change in air pressure constitutes a pneumatic device, then this would apply to any fan (including those integral to motors / speed controllers), spoked wheel (flywheel shooters move a LOT of air around), etc. Such an absolutist position is just ridiculous.