Yes, but IP addresses are linked to your general location. Mjshroomer and 'Coatl live on opposite sides of the US (according to their posts). And at least when they both posted on the Shroomery, their IP addresses were consistent with their putative locations.

Unless they've both taken to using proxies, and post via the same proxy, I call BS on the claim that they're posting from the same IP.  They are definitely different people.