Stopping Shopping

Does anyone have any suggestions for how I can stop the bunnies from hopping off to shop and expand their seed holdings? I tried sending out their pictures to all of the stores with a note not to sell to them, but would you believe that they say that they can't refuse, that it would be species discrimination or something? So, what can I do to stop them? So many places around here foolishly sell cheap seed too. Perhaps I could figure a way to switch their change for Chucky Cheese tokens?