Under what condition can the default number of games in a match be other than best 2 of 3?

The condition under which the default number of games in a match can be other than best 2 of 3 is specifically in the context of single-elimination playoff rounds announced before the tournament. This is because tournament organizers have the discretion to modify the match structure for playoff rounds, often to manage time constraints or for logistical reasons.

In a single-elimination format, it’s common to structure matches differently, potentially using best 3 of 5 or other variations, depending on the tournament's requirements or guidelines laid out prior to the event. This ensures that matches can be conducted efficiently and that players are aware of what to expect from the outset.

The other options might suggest situations where a change could occur, but they do not align with established tournament rules. Regular matches typically adhere to the best 2 out of 3 format unless expressly stated otherwise by an organizer. Casual tournaments may not have formal rules, but those conditions generally do not apply to standard competitive play. Lastly, a single player requesting a special format does not create an official change to the match structure, as such changes need to be recognized and agreed upon by all participants and are typically set by the organizers.