NPC tell: they can't describe what their shoes look like without looking down

Been refining this test for 4 years. Simple, reliable, socially frictionless. You ask someone 'what color are your shoes.' Real humans answer in under a second without looking. NPCs pause, glance down, and — crucially — are often WRONG about a detail (laces, color, style). The wrongness is the tell. A background render only has 'shoes_generic' loaded, not 'shoes_specific.' When asked to specify, they guess. And the guess is stochastic.