In 1989, BYU’s football team wore a red dot sticker on their helmets during their game against the University of Hawaii to honor offensive lineman Mo Elewonibi.

Elewonibi had recently lost his father, and the red dot symbolized the team’s support for him during that difficult time. It was a gesture of solidarity and remembrance, demonstrating the team’s unity and care for one of their own.

Mo Elewonibi was a standout player and later won the Outland Trophy that same year, which is awarded to the nation’s top interior lineman.

Link to source: https://uni-watch.com/2018/09/26/solved-the-mystery-of-byus-red-dot/