This Colorless deck's plan revolves around a handful of named engines — Karn, the Great Creator, The One Ring, Grim Monolith — so Disruptor Flute naming any of these taxes the spell by {3}, often more mana than they have access to early. Flute can also name Urza's Saga to shut off its Construct-making ability, but it can't tax the Saga itself, since it's a land that is played rather than cast. Chancellor of the Annex is dead weight since the opponent is mostly colorless and can simply pay the {1} tax, while also being a slow 7-drop in a prison mirror where we want to be proactive. The extra Broadside Bombardiers give more ways to close the game with sacrifice-fueled damage before they assemble a lock, and Trinisphere/Chalice of the Void line up well since this matchup is a race to tax the other's mana first.