Answered: Pneumatic Piston not being Connected to Resevoir

We are having a disagreement (between us and our coach) that we can leave a dual acting piston, if we do not not need to it to push out, and just need the returning motion, can we leave the air input hole open. We are wondering if we can leave the piston disconnected from the resevoir to absorb air from the outside using some things (such as rubber bands and a lever) to push out. We have questions mainly if this would work, and especially if it is legal.

Thank you in advanced.

Yes, this is legal.