I agree that the integrity of the thread could be called in to question, BUT the appropriate way to deal with it is to report it to the mods and have them investigate. After all the admins can see the full IP address and verify if it is the same person, or just happens to be 2 people who live in the same area with the same internet provider.
Raise it with the mods or leave it be.
My understanding is that one of the User IDs in question has already been suspended so really it is a moot point anyway ?
ESN Price at posting:
0.2¢ Sentiment: Hold Disclosure: Held