1. Because the caller ID is "Blocked at source", the receiving system cannot recover what was never sent from the caller.
2. No.
Be aware however, that each computer, internet phone etc which is "on the Internet" (WAN = Wide Area Network), or (LAN) Local Area Network requires an individual MAC address.
The unique MAC address, like the IP Address, is required for hardware items to be able to send/receive data to/from each other in a proper manner.
Be aware that there are ways to establish identity of any caller to a VOIP system, and "Authorities" often do that by Voice Recognition software, as well as "Other Means".
It is never safe to assume that any communication is safe and anonymous.
Please remember the Quotation in "Yes Minister" UK TV Series, by from Sir Humphrey Appleby: "He that would keep a secret must keep it secret that he hath a secret to keep."
Kind Regards....
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