Sunk Cost

Reward equal to the risk is an expected part of the game. Emphasis on the “game” part of that sentence. Because players know it’s a game certain things are just expected, almost assumed. Such as a reward equivalent to the risk endured to claim said reward. Otherwise the ratio of risk to reward is imbalanced.

This is one of those funny situations where it is not just the metagame, as the narrative also validates the player’s expectations. The more dangerous a trapped hallway the better the reward should be at the end, to justify the expense and necessity of the traps. No one fills a room full of traps out of boredom, they’re guarding something.