If your young child claimed that his sibling hit him without being provoked, you would not punish his brother without gathering some evidence to support this. If an employee claims her coworker stole money from the employer, an employer would not fire said employee without verifying evidence a theft actually occurred and that the employee is responsible. If someone claims your significant other is cheating on you, then you would not end the relationship without some form of corroboration and/or admission of guilt. If you claim you are the owner of a specific bank account, a bank employee will not allow you to withdraw funds from said account without verifying this is true.