When golfers play in a tournament or a competition, they're typically assigned a tee time when their round is supposed to start. (This typically happens for recreational golfers just playing for fun, too.)
However, sometimes life get in the way. People forget their tee time. Maybe they oversleep for some reason. They get ill and have a terrible night. They just get mixed up or lose track of time on the range. There are any number of reasons why a golfer might wind up showing up late for their tee time, and that's a problem under the Rules of Golf.
What happens under the Rules of Golf when a player misses their tee time?
Regardless of the reason why a player might miss their tee time, the USGA and the Rules of Golf are crystal clear about the penalty for missing a tee time. If a golfer misses their tee time at the US Open or any other tournament, they're disqualified. That's it.
As of 2019, Rule 5-3, which covers showing up on time, was slightly amended to give a golfer a five-minute grace period to get on the tee and play. If they get going within the five-minute grace period, a player gets a two-stroke penalty but they can at least continue.
However, the USGA will probably go out of its way to afford alternates a chance to compete if it appears a player is going to miss their tee time by a wide margin. This would allow the player stuck in traffic to withdraw from the event and then insert an alternate at the last possible second.
The USGA has said it will go out of its way to make sure players are aware of traffic concerns, reminding them by text message of getting to the property well ahead of their tee times. Expect to see players trying to show up more than 2 hours ahead of the tee time -- you know, just in case. However, a tournament committee can decide to exempt a player from penalty in the event of "extraorindary circumstances," determined at their discretion.
What you won't see, though, is a tee time moved earlier in the day from the published, scheduled time.
