Players can already generate kill rights on their alts/friends, to the same result.
They cant, or rather, it wouldnt do what you think it would,
Dynamic IPs, shared IPs, proxy IPs, VPN and IP tunnelling etc all make it impossible to ascertain which account is associated with which person, via IP.
IP addresses are not “hardset” in the way you think they are, nor are they associated with the account.
For CCP, the accounts exist as an individual account identified by its unique login/password data. They can investigate what IPs that account accesses EVE through/from, but its not conclusive, because IPs are not constant for that client/player.
For example, If I travel a lot, I might play EVE on my account from Finland today on my home IP, and Singapore tomorrow on a hotel IP network on a vacation there.
See what I mean?