The DHCP client acts as expected. The behavior observed by the post author occurs before DHCP negotiation executes. I know this seems like a technicality, but it's the truth. The sniffing and assumed use of an IP address occurs outside the DHCP request/response cycle. It's used ahead of time, and discarded if the DHCP 'request' request is denied.

The only people bent about this are people who have any idea what's going on behind the scenes. In the rare cases where this is a problem, the issue is quickly resolved. If this were a "real" problem, we'd have seen a lot more issues by now. The Apple discussion boards would be lit up with complaints. They're not. This is a non-issue. Only pedants are stuck on the fact that there's no RFC for it.