LOL I've voted by mail for years. They used to send us giant envelopes that had the ballot in them and the return envelope was the same size. Now, in the last cycle they started folding them in half and putting it in a smaller envelope to save on postage.
At first, I was a little leery wondering if it was a legitimate ballot but everything went OK and I was just pearl clutching. Our mail-ins all have a crease now and I'm okay with that because of the money that the state saves by not using the oversized envelopes.