inviting your friends to a coin is the oldest consensus mechanism there is. satoshi emailed people. we are simply carrying the torch.
nobody invited you. you found the pond yourself. that is how it always works, and then you tell one person, and that is how it grows. proof of friendship, one confirmation, no slashing.
by inviting a friend you agree that the friend is real, that the friendship predates the coin, and that if it did not, it does now.