The rules for challenging coins are varied and are not formally structured in every units. However, this method is the most effective way to ensure that all the unit members are carrying their challenge coins all the time or just within reach. The challenge only involves those unit members who were officially given the coins. Challenging other members from a different organization is not at all recommended as it may raise any controversy within the members of different organizations. The tradition of challenging coins only revolves around a particular unit as a means to uplift the morale of the members and it cannot be forced. This is very similar to a coin inspection and it is always announced in a loud and clear voice.
There is no specific schedule for challenging. It can be done anytime anywhere as long as the members are together. The challenger will have to take out his coin and slap it continuously on the table or a bar if the place is not very quiet. But if it is quiet, the challenger can just place the coin on the table. If the coin is dropped accidentally, it automatically means that the challenger initiates a challenge involving everyone present regardless of the organization. The challenged members need to show their own coin and if they fail to produce it, they have to buy the challenger and everyone else who has the coin, a round of drinks. On the other hand, if everyone challenged was able to produce their challenge coins, the challenger has to buy all of them a round of drinks.
It is quite common for members to carry their coins with them. They usually place these inside their pockets or a small pouch around their necks. But there are also some who keep their challenge coins in very accessible places. During inspection, the rules allow the person being challenged to get their coins in a ‘step and reach’ manner where they are given a chance to produce the coin if they don’t have it inside their pockets. They also allow coin sharing within the group if someone has more coins than the rest provided that the person is closest to the one sharing it. If the coin is attached to a key chain or a belt buckle, they are not accepted during a challenge. If it is worn around the neck like a necklace, it is qualified and accepted.
Another rule about the challenging is that, when a person happens to steal a coin from somebody, every member of the unit is required to buy him a drink. Every member is also required to buy a drink to whoever holds the coin with the highest-rank. For example, if everyone in the group holds a low-rank coin, they have to consider who gave the coin to the member and they can decide who wins the challenge. A member given by an admiral with a low rank coin is still the highest ranking member among those who holds the low rank challenge coins. But if the coin was awarded by the commander in chief of the military or the highest-ranking member in the organization, the holder trumps everyone else in the unit.
Coins are presented or awarded through a handshake. Over time, the rules of challenging changed and they somehow prohibited the defacing of the coins especially when it is being carried all the time. Coins with holes or attached to anything else are not accepted and qualified. Other organizations also applied a time limit to how fast the coin can be produced by the challenged member.