Okay, so I am not a lawyer but this is me trying to cover my ass the best that I can. By checking this box you are agreeing to only send email if either of the two situation are true:

1. You are conducting a formal and legal penetration test in which you have the explicit permission of the organization that represents the target, and such a targeted attack is outlined in your planned attack scope.
2. You are a student or learning about mail systems and want to learn more about mail security. If this is the case, you should only be spoofing accounts that you have legal access to, or have otherwise gotten permission to use. emails sent for the sake of learning should not attempt to steal credentials or other sensitive information, even as a 'joke' or 'prank.'

Using this application for any other reason falls outside of its intended use and is not endorsed, encouraged, or approved by the application's creator or its contributors. This is especially true if this application is being used to send spam messages or commit fraud. This mailer does little to protect the identity of where it was truly sent and the message can be easily tracked back to the originator. It only masks the identity on a surface level inside of a mail client.