Rule 203 states a member should not approve any statements that do not follow Generally Accepted Accounting Principles, also known as GAAP, according to the AICPA Code of Professional Conduct. CPAs also cannot lie about being unaware if changes are made to a financial statement to comply with GAAP.
The only exception allowed by the AICPA applies under unusual circumstances when following those accounting principles would be misleading. In that case, the accountant must explain the reasons for the departure from those principles.
Rule 203 assumes observance of accounting principles will result in financial statements that are correct in almost all instances, according to the New York State Society of CPAs. However, the rule is flexible when applied to unusual circumstances in which traditional accounting principles would be misleading. Examples of unusual circumstances include the passage of new legislation or the creation of a new type of business transaction.