Hey,
I know Im not the first one to design an adapter for the Sodastream gas cannisters and Im resonable confident that one could design around the anti refill trap.
The question now is if I test my parts in plastic and the give it to shapeways to metal print it and then put in a rubber seal would you trust this part?
I can imagine there is quite a transition between the plastic and the metal and even the metal parts would need 2-3 iterations, but would this part be reliable enough?