It occurred to me that if I created a wallet today, people might be able to send money to that wallet as early as the creation of the BTC blockchain. It'd be secure because once an operator in the past had sent the payment they'd no longer be able to access it. Nobody in fact would be able to access that wealth before my key had been created. In such a circumstance, would I be, in creating the wallet, just accessing the wallet with funds already in it? Do I have the wrong idea about how this works, or would BTC be a great way of receiving secure payments from agents in the past?
Could time travelers already be using wallets for which private keys haven't even been generated yet?