Unfair Fight Reduction is not applied to deaths outside guild wars because the experience rate is significantly higher here than on real Tibia, and because our rules allow you to use a bot to assist your gameplay. A death should hurt, and matter, especially when you die to players. This encourages sneaking when someone is refusing to fight their enemies in guild wars.
Unfair Fight Reduction is enabled in guild wars to encourage for more and longer guild wars on the server, because guild wars is one of the primary reasons why many are playing here. It doesn't mean we don't care about the RPG aspect of the game, we do, but that doesn't mean a death should be something you laugh about because your death penalty is reduced by 80% when you get sneaked by players outside a guild war.