This is very true. If a male is smiling, it means he is showing his submission and in turn is subconsciously treated by other males as a lower level male. The exact system of hierarchy signs exists in chimps. For me it seems like russians together with some other cultures managed to save this body language component as meaningful way of interaction, in contrast with western way of smiling meaning level zero relationship. Because if you truly can not tell fake smile from real one, the meaning of a smile is lost. That's why I also am not going to ever accept "always smiling" thing, even if I would go to live in western country. A smile should be a sign of affection, not a sign of neutral stance. We have neutral face impression for that. And if you interpret neutral face impression as "something wrong", what are you using "worried" face impression? It just seems wrong to always smile, even considering "brain hacking" thing.