Reposting because I attached the wrong pic:
This just happened to me too. The other player cast Key to The Archive and it has a Spellbook, and Demonic Tutor is among those Spellbook cards.
I understand why it was banned, but if I can still be played through the Spellbook, I think it should be legal in Historic Brawl or removed from that and any other Spellbook that contains Demonic Tutor.
Reposting because I attached the wrong pic:
This just happened to me too. The other player cast Key to The Archive and it has a Spellbook, and Demonic Tutor is among those Spellbook cards.
I understand why it was banned, but if I can still be played through the Spellbook, I think it should be legal in Historic Brawl or removed from that and any other Spellbook that contains Demonic Tutor.