I remember this Easter egg, that if direct light/ambient light/the third lighting option in the environment settings is set lighter than the other two, a player with shaders on will have an easier job seeing than people with no shaders. I used this technique on that old hide n seek server from a year ago, because the host had the settings set perfectly. I wish I could remember what lighting settings were in effect. I think it was direct light being brightest, but not sure. This would be an incentive for people to use shaders instead of no shaders.