Even at highest levels players make significantly but human mistakes. On the other hand there exist a great opening theory with lines studied in deepth, especially the mainlines. Isn't the precision of theory evaluation and human imprecision contradicting? Is it generally difficult to punish small opening sins even at the highest (human) level (Evans-Gambit, Cozio defense, 1. ... a6)? If so is the fact that most advanced players learn and play some kind of mainlines just some kind of gentlemen's agreement? Or do they score significantly better?