Reason shapes the future, but superstition infects the present.
—IAIN M. BANKS, THE STATE OF THE ART
When creating models for rational actors, it makes sense to examine an edge case: What would a perfect player do? And the larger your game is, the more looking through the lens of the actions of a perfect player makes sense. A game with a few dozen players can get by with some loopholes. A game with millions of players is likely to have a few players who can ferret out all the possible exploits. Players are still finding exploits in the original Super Mario Bros. 30 years after it was published (http://kotaku.com/decades-later-someones-discovered-a-new-super-mario-br-1591884544)
If you assume all your players are ...