If the receiver is registered with #cash they have nothing to do to receive payments made to them with #cash. The amount sent to them is simply credited to their bank account.

If the receiver is not registered then TR2 will generate a text from the sender detailing the amount that the sender is trying to send and giving instructions on how to register to receive this payment.

People pay people they know. Therefore, as this prompt has come from a friend (who is stored on your address book) and the payment is for an amount known to be owing then the prompt to register will be trusted and followed.

Now the receiver can also become a sender. This will allow #cash to grow virally.