1) No tattling; 2) standing up for others when necessary, like Batman; 3) keeping one's word; 4) not being a wuss; 5) sharing; 6) not retelling rules like a wet blanket; 7) not implicating others when busted, regardless of the punishment for silence.
Playground honor was hegemonic when parents would beat your ass for shit; and it was considered unfair to subject even enemies to such treatment. However, Playground Honor remains important to allow play regardless of concern for hygiene, physical safety, and "feelings."
"Nobody likes a tattle tale," a common aphorism, central to the ethic of Playground Honor, and indicates the punishment for violating this system of ethics: Playground Honor is enforced by de-facto ostracism of violators, including tattles, whiners, and worry-warts.
Playground honor is supported by caretakers desire not to have to be bothered by punk ass tattle tales. However, some adults also believe that it is necessary to allow the inevitable injustices and dangers of childhood to be solved by children themselves, in order that they develop moral courage and a sense of self-responsibility.
NOTE: Playground honor is not limited to childhood, and may be used describe the moral decision not to intervene or seek out authority to intervene in someone else's problems during young adulthood.