A dm I know told me the other day that barbarians cant tell friend from foe. His reasoning was that the barb cant use int based skills and being able to tell friend from foe is an intelligence based skill 
Does this arguement hold any water? Are there any other strange fringe effects of things that dont make any sense in game but are probably true according to the barbs rage entry?

Does this arguement hold any water? Are there any other strange fringe effects of things that dont make any sense in game but are probably true according to the barbs rage entry?