If governments were to do that, they would also be forced to solve the problem of the routing table explosion. Which is a hard problem. As for unique ID - it's

If governments were to do that, they would also be forced to solve the problem of the routing table explosion. Which is a hard problem. As for unique ID - it's already doable and being done without any IPv6. Read up on evercookie. There was an article on HN a while ago about a bunch of advertisers doing just that. This is worse than the government having it - not only it gets abused, but someone gets rich on this.