Thoughts as I Stuff Wedding Invites

When you send mail without enough postage, the mailman returns the mail to the address that is listed on the top left of the envelope (the sender). Although I'm sure it is some sort of felony, couldn't you just put the address of the person you are sending your mail to on the upper left corner, your own address in the center, and then just see if they send it to the person you are trying to send mail to for free?