I never thought of that attack vector. In the usa you can not open amazon lockers twice, but I could in theory still perform this attack. It would require me telling amazon customer service to give me a new locker code.
Maybe I've overthought it. Maybe it's not possible. Maybe it leads to you (and jail), maybe other find another crack/flaw.
The point was that a honest business would ... try to be honest (and there are still risks, as I said), while a dishonest business could already have the recipe for scam, I don't know. A theoretical chance, no matter how small, probably exist. And.. we're back to the trust issue
However, good luck!