I think there is a subtle bug in his second two person::~person examples. Specifically, from the perspective of other threads an object is no longer valid once its destructor has been called. So, imagine two person objects side-by-side in a linked list. If they are both deleted simultaneously and both destructors get called at the same time, they can no longer safely unlink from each other even with locking because they are technically no longer valid.

The first two examples don't have this problem though.