Why are League Events / Rounds Locked?
Locking an Event / Round will prevent any Configuration & Scoring changes to that Event / Round by accident. Once an Event / Round is Locked, you will need to Unlock the Event / Round before making a change.
Player Statistics Generated
Some player statistics are generated for the Player when the Event / Round is locked, it is always good practice to Lock the Event / Round once it is completed.
Please refer to the following article on how to Lock / Unlock an Event / Round Event / Round - Lock & Unlock