[Didn't watched the Video]
I got a feeling that he's talking about "
Brain Wallet", if it is, there's a huge risk in security here.
If it's not, he might just wanted to know more about what's blockchain under the hood.
(a) transfer funds to keys that have not even been initiated? Don't you need a wallet to generate that for you?
In addition to what others said, in simple words:
[a] You can receive funds in any address anytime as long as you have its
Private key pair even without a wallet or internet. All you need is a piece of paper and a pen.
Addresses which are based from Pub keys aren't "
initiated" in order to be valid. Even if it is not yet used, every address is valid as long as it was correctly derived from a valid Public key which is derived from the Private key (
wallets do this automatically but it's possible to compute manually).
More info:
Bitcoin Wiki