All of that hard work that players have done throughout the season and playoffs, all of their dreams they've been chasing since they were kids, all culminates into a Stanley Cup win. Despite all this, there are still rules to follow, however Matthew Tkachuk decided to completely ignore them and breached them.
Tkachuk stands by his statement that he had no idea and would not have done that if he knew, and puts all the blame on his brother Brady of the Ottawa Senators, who gave him the idea to go into the ocean with the Cup. Matthew did redeem himself, as he took the Cup to the St. Louis Children's Hospital and let some sick kids enjoy moments with the precious trophy.