The objective of the Alert system is for both pairs at the table to have equal access to all information contained in any auction. In order to meet this goal, it is necessary that all players understand and practice the principles of Full Disclosure and Active Ethics. Ethical bridge players will recognize the obligation to give complete explanations. They will accept the fact that any such information is entirely for the benefit of the opponents, and may not be used to assist their own partnership.
This procedure uses the admittedly "fuzzy" terminology of "highly unusual and unexpected" as the best practical solution to simplifying the Alert Procedure. "Highly unusual and unexpected" should be determined in light of historical usage rather than local geographical usage. To ensure full disclosure, however, at the end of the auction and before the opening lead declarers are encouraged to volunteer to explain the auction (including available inferences).
According to the Laws of Duplicate Contract Bridge: Law 40.B. Concealed Partnership Understandings Prohibited
A player may not make a call or play based on a special partnership understanding unless an opposing pair may reasonably be expected to understand its meaning or unless his side discloses the use of such call or play in accordance with the regulations of the sponsoring organization.
Bridge is not a game of secret messages; the auction belongs to everyone at the table.
Remember that the opponents are entitled to know the agreed meaning of all calls.
The bidding side has an obligation to disclose its agreements according to the procedures established by ACBL.
When asked, the bidding side must give a full explanation of the agreement. Stating the common or popular name of the convention is not sufficient.
The opponents need not ask exactly the "right" question.
Any request for information should be the trigger. Opponents need only indicate the desire for information - all relevant disclosure should be given automatically.