Why “I cut, you choose” works best with two people
The rule gives the cutter a strong reason to divide carefully: the other person gets to pick first. If one piece looks larger or more appealing to the chooser, the cutter risks being left with the worse one. The trick is that “fair” here means fair according to each person’s own judgment, not necessarily identical in weight or appearance.
With more people, that simple safeguard weakens. One cut can create two pieces, but a group needs a whole set of portions. If the cutter divides the cake and everyone else chooses in turn, early pickers have more options. The cutter, who chooses last, may have little control over what remains. And a division that looks even to the cutter may not look even to someone who values the frosting, filling, or corner pieces differently.
More diners mean more comparisons
Fairness becomes harder to manage because each person can compare their portion with several others. A small difference that might go unnoticed in a two-person split can stand out in a larger group: someone may see a piece with more decoration, a preferred flavor, or simply a more generous-looking shape. The cutter must anticipate not just one person’s possible objection, but many different preferences.
That does not mean a larger group cannot divide a cake fairly. It means the two-person rule no longer guarantees a result everyone will accept. People can rotate who cuts and chooses, divide the cake into smaller portions, or agree on a different method when preferences are uneven. The more tastes and comparisons involved, the more useful it is to make the procedure clear before the knife comes out.
