Comment by yyyk

IPv6 discussions keep having this scenario - which is barely relevant to how nearly all IPv4 LANs operate.

It's assuming a huge zero-trust point-to-point network where it's a rare scenario for IPv4 LANs. IPv4 LANs tend to assume the internal network is semi-trusted and route through hubs, so merging networks is a bad idea even when the mapping does not conflict (which often doesn't if the companies are tiny like most are). Even in a zero-trust point-to-point environment you'd want to review the other side, convert it to your software, etc. And the people on the being acquired side have little reason to care too.

It's a scenario that's only relevant for a huge company constantly acquiring other companies that operates via zero-trust point-to-point networking and strongly tries to minimize human review - basically Google/Alphabet.