Joseph,
Call the consumer protection agencies of each state and ask them if such a return policy, when clearly stated up front, violates any state laws. Come back to us and report, after you made those phone calls. Regarding your hypothetical case, one would have to review all applicable laws in each city and state and then we can answer you, until then, as long as any policy is enforced evenly to all across all customers (and the policy itself is legal) then they can do whatever they wish. It may be (note: I said, may, since I dont know what motivated such a policy to begin with) a bad business decision, but bad business decisions are not illegal.