A custom is a way of acting in a manner that has been continued constantly over a long period of time.
There are several policies with regard to conduct which an Army Soldier needs to pay particularly close attention to. Furthermore, military discipline denotes that all officers should be loyal to their men, taking genuine interest in their welfare and making certain that their rights and privileges are granted as they should Department of the Army, Lionel Wijesiri "When music and courtesy are better understood and appreciated, there will be no war.
Courtesy is displayed at all times and should basically ensure that the relationship or conduct of the involved soldiers fosters good relationship amongst them. It is give and take.
Failing to conduct ones-self in these mannerisms just labels that person as careless or raised poorly. When out of uniform, cadets are expected to control their behavior with regard to alcohol.
I personally feel that the modern Army's way of promoting individuals is biased and unfair.