Most people would consider it to be poor sportsmanship, but you technically are allowed to do it
You lose the Glint-Horn Buccaneer combo, but Franciscos part of plenty of combos itself, and youre in the right colors for the Oracle-Consult combo

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Do I get to count Now I Know My ABC's when counting letters for the win condition
Kethis, the Hidden Hand Without the protection of Teferi, Time Raveler, Kethis, the Hidden Hand is a deck with a powerful combo finish that can still be disrupted