Posting proofs? Can you elaborate a bit? The date on the forum itself can't be changed (but time zone can, that will affect the date, though the user has a time zone to choose in his profile) but anything on the photo can be tampered.
I was wondering if an Admin COULD set the time to whatever he wants and then does a post which is supposed to have been made at that time in the past (to proof something). Like you said, it´s not possible. That was my question.