[yason]

The latency could be what it is but to clarify the core of my assumption is that:

1) sending money to anyone or receiving money from anyone happens mechanically (nobody will step in and say sending $200 to your friend will be cancelled because it looks like a merchant transfer); and

2) when banks do clear the transfer it is cleared for real, and if you see the money on your account it's yours for real by that time.

This would be in opposition to what Venmo does, i.e. lies to you that you've received the money and you haven't. Or can it happen in US accounts that you see a fresh deposit on your account but the next day it won't be there anymore?