When Keith attempted to slip a card from his wristband to the disk, it set off the cheat-prevention alarm, indicating that the Disk would not accept any cards on the Disk aside legitimate ones within the Duel, though this appears to be a feature of all the Duel Disks used in the arc as a whole, as indicated by the rules shown in the back of Volume Four (Keith had no knowledge of this due to the Disk being developed after his Penalty Game.)
#9 Oh, I didn't think we were counting things that keep cards from eventually landing in the graveyard
It did feel pretty bad to lose after taking such an early lead, but I was honestly just impressed he was able to pull off such a wild combo
Step 10: Collation & Packaging (Printer/Finishing Facility) The last step of the process is packaging the cards into sealed products so they can be shipped out and sold to you
But it doesnt contribute to the mana base in the same way that another Forest or Swamp would as a colorless land
Its the kind of protection you want in decks led by the best zombie commanders or grindy black shells that need their engine to stick