I just realized something! My daughter’s wedding invitations went out recently (she got them from some popular online site), and the envelopes had a gold-outlined rectangle in the middle, where the address should go. I thought maybe it was to make sure they got scanned correctly at the post office, but now I’m thinking it’s so the senders will know where to put the address 
Now I’m tempted to peel the stamp off to see if there’s fine print behind it that says “the stamp goes here”.
I was always fascinated by all my business return envelopes that said “place proper postage; post office will not deliver without postage” in box which would be covered by stamp.
One thing I always taught my kids was how be clean and a good house guest when staying with other people. Not leaving hair in someone’s shower drain, don’t leave the wastebasket overflowing, make your bed when you leave, etc. My kids aren’t perfect and neither am I, but these are always nice things to know!
I recall D getting an envelope from state of CA warning her they would consider all her wages forfeited if she didn’t deposit her checks & she could get duplicates as they noted she hadn’t deposited them.
She sheepishly said she was surprised they weren’t Auto-deposited into her account as they had been with prior (different) employer.