The Department of Work and Pensions, UK has an entire /8

Wed Sep 19 13:24:16 UTC 2012

On Wed, Sep 19, 2012 at 12:07:33AM -0500, Jimmy Hess wrote:
> Assume you have a public IPv4 assignment,   and someone else
> starts routing your assignment...  "legitimately" or not, RIR allocation
> transferred to them, or not.
> 
> There might be a record created in a database, and/or internet routing
> tables regarding someone else using the same range for a connected network.
> 
> But your unconnected network, is unaffected.

Ahh...  But the network may not be unconnected.  Just because *you*
don't have a path to it doesn't mean others are similarly disconnected.
All of those "others" would be affected.

> You are going to have a hard time getting a court to take your case,
> if the loss/damages to your operation are $0,  because your network is
> unconnected, and its operation is not impaired by someone else's use,
> and the address ranges' appearance in the global tables.

Think about a company that has thousands of private interconnects with
other companies.  Unique address space would remove the chance of
RFC1918 space clash, and any of the bad effects of NAT. (e.g The network
*works* as it was originally designed.)

Such a network would not have $0 in loss/damage when the partners can't
reach it due to a rogue announcement.

The Internet is not the same from all viewpoints.