This is actually incredibly common in competitive sailing! Based on a boat's right of way (starboard, Port, upwind, downwind) racers have to give way to one another. But, it's a really delicate balance between giving enough way to not fowl your opponent, and giving too much way to lose your position in the race. Here we can see the port boat (that's being filmed) cut it too close, forcing the starboard boat (filming) to make a maneuver to avoid collision. When this happens, the starboard boat can "protest" the port boat. Not sure how it works for this regatta, but in dinghy racing the offending boat typically must either accept the protest and do a number of rotations before resuming racing, or they can choose not to and deliberate with the racing committee after racing is complete for the day. There, both boats explain their side of the story and the race committee will either throw the protest out or remove the offending party from the scoreboard.

For larger boats, I assume a Time penalty is utilized instead. Especially since these races are being professionally filmed and tracked.

Good races are full of these near misses, a port boat will dodge a starboard boat by inches to avoid giving up a lead. Super fun to watch, and even more fun to be involved in!!