This has been suggested several times, but it turns out it's not on admin's top priority list. At least not for this current forum software.

2FA would be nice, but IMO the email notifications provide many of the same benefits, so it's not high on my to-do list.

But there's hope for the new forum software

Quote

Any plans for implementing some sort of a 2FA in the new forum? (this is especially important for people conducting trades over the forum)

Yes, there will be 2FA.

Hmm, I don't see how email notifications provide any benefits of 2FA. But good to know that 2FA is in plans for vNext of the forum.