If a player completes the first 18 holes in a 72 hole stroke play event and then hits a few shots for a commercial, what is the ruling?

In this situation, the player has engaged in a practice or commercial activity during a round of play after completing the first 18 holes of a 72-hole stroke play event. According to the Rules of Golf, specifically regarding practice sessions, players are not allowed to practice on the course during a stipulated round.

As a result, engaging in such practice after completing the designated play requires the player to be disqualified from that round. This is to ensure that all competitors are following the same rules and that no player is gaining an unfair advantage or disrupting the competition with non-competitive activities. Therefore, disqualification is the appropriate ruling in this case, as it maintains the integrity of the tournament and adheres to the established rules governing player conduct during play.