Doing that will give you a couple of benefits.

1. The script will only accept email commands from a list of people by decrypting/verifying with their public key.

2. You get a good username/passowrd type of environment because only people with the private key can create the email command.

Yes, this would add complexity, and you couldn't send the email command from just any computer on the internet, you would need PGP and the private key. But the security benefits would be worth it. You could leave the script running all the time.

Bryce