In AdS/CFT partition functions of decoupled copies of the CFT factorize. In bulk computations of such quantities contributions from spacetime wormholes which link separate asymptotic boundaries threaten to spoil this property, leading to a “factorization puzzle.” Certain simple models like JT gravity and the SYK model have wormholes, but bulk computations in them correspond to averages over an ensemble of boundary systems. These averages need not factorize. We can formulate a toy version of the factorization puzzle in such models by focusing on a specific member of the ensemble where partition functions will again factorize. In this talk we discuss bulk computations of partition functions for (sometimes approximately) fixed members of the ensemble in three simple models: the topological model introduced by Marolf and Maxfield (the “MM model”), JT gravity, and the SYK model, and give an effective description of the factorization mechanism.