I was wondering this same thing this last week in a competition with my friend. We both reached the exact same number of points on the last day. I could have continued to wear my watch and win because he had reached his maximum points for the day, but instead I kept it off to answer the question of what happens in a tie.
The notification you get the next day is that you ended in a tie, but it still gives both of you the award for winning! So it’s really a win-win situation :)