So imagine the bank give all objects in their company an address. The desk has an address, the fridge has an address and so on. Bank accounts have an address too. All these addresses look the same and use the same system to interact with them. The problem is that Johnny wanted to deposit $50 dollar into his account, but he accidentally used the wrong address, and now the fridge in the the bank's kitchen on the 5th floor now owns $50. To his dismay, there is nobody to send his funds back since no human owns the fridge and nobody is even able to break the fridge open to get it out. Don't blame the fridge they say, don't blame the bank they say, don't blame the currency or the address system or the person who made the rules so that fridge addresses and bank account addresses work the same. No, lets blame Johnny, the dumb ignorant fool who doesn't understand the glory of the banks special addressing system. It is working as intended. He should've known better, he should've read the docs etc. Fuck Johnny and his $50.

You’re using a different definition of the word invalid.

Obviously the person you replied to meant invalid in the sense of “not intended to receive funds”

It would have been a competent design decision for a system to require some type of initial registration of intent to receive funds for an address in order for a transaction to post.

Most people setting up mailservers don’t consider a catch-all forwarding to /dev/null a valid inbox. And no sane mailserver software forwards to /dev/null by default if you don’t explicitly tell it what to do when it receives email it isn’t supposed to receive.

A “valid” address locking up funds sent to it without recourse is /dev/null.