[EricH]

The second one refers to a diaphragm, or flexible membrane, to convert air force into mechanical force. I think this the type of device that you're asking about. The GDC has specifically pointed to that as not legal.

There was one--in fact, the first one in the pneumatics--about using inflatable items. However, it doesn't cover inflatables that are inflated using the compressor's air.

http://forums.usfirst.org/showthread.php?t=13703

You might reference it when you ask, something to the effect of, "Regarding [previous link], does the answer change if the inflatable item is COTS, pressure rated to at least 125 PSI, and inflated using the onboard FRC pneumatics system? If not, which rule does it violate?"