It is the player’s responsibility to ensure that his clubs conform with the Rules and if in doubt about a particular club, he would be well advised not to carry it. However, such advice is not always appropriate, particularly when a query arises during or after a competition, in which case a decision is required.
The vast majority of golf clubs conform to the Rules and, therefore, equipment conformance queries of this kind are rare. However, queries do arise from time to time and Officials need to know how to deal with them. It is important to remember that it is a player’s responsibility to play with conforming clubs. He or she cannot shift this responsibility to the Official. For their part, Officials should respond to such queries with due consideration to all parties involved. Appropriate consultations should be made (i.e. referencing the Equipment Rules, the Rules of Golf, and the Interpretation of the Rules of Golfs, contacting The R&A or USGA, etc.). If it is not possible to give a definitive ruling straight away, a Duration of Competition or Duration of Round Answer should be given (but see A7).
In giving Duration of Competition or Duration of Round Answers, Officials in doubt should err towards deeming clubs to conform. Penalizing a player for carrying or using a club that later turns out to be conforming is a more serious error than allowing use of a club which later turns out to be non-conforming.