Once a competition has closed, there is plenty of time to contact The R&A or USGA to find out whether the club conforms or not and/ or to submit the club. If it turns out that the club is non-conforming, the decision whether to disqualify the player or not depends on whether he or she knew the club was non-conforming (see Rule 20.2e(2)). This is a question of fact, but in determining the facts, the Committee may wish to consider other evidence as well as the player’s own statement.
Conclusion
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 Clarifications on 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 making a stroke with 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.