The decal only does one thing. It proves you purchased a new set of divemaster materials. You have to put it on your application for it to be processed. You keep it until your training is complete and you have met all requirements and send your application in. Your instructor never actually needs to even see your decal if you mail in your own application like I did. Instructor only needs to sign.
You say this instructor is a friend?
You say this instructor is a friend?