I used to do that too. The reason I stopped is because I found out that in the event of a major straggler where the postage is far enough out of date, on a letter that has the same address for the return as the send-to, the post office won't return it. I seem to remember reading somewhere that as long as the postage is within 10% of the required total, it will still get sent. So with postage now being 44 cents, it will likely still make it on a 41-cent stamp, but won't on a 39-cent.
Whereas if the address is different, it will be returned to the sender-- in this case the athlete. I figure the athlete will either add the extra postage, or keep it for himself to possibly send to someone else. At least the Post Office doesn't end up keeping it.
