That's a good point too and something we hadn't considered. Would it work if the package was just delivered in the mail as usual and they could open it when they got home as something to look forward to?
That assumes that old people live at home / have a regular mail box.
What if they live in a nursing home or similar? Although 4x6 (10x15cm) is postcard format, so usual mailboxes should fit quite a number of those just fine.
The photos come in a pretty much regular sized envelope that fits in small mailboxes. I do like the idea of letting people pause a delay a delivery for whatever reason they want, or maybe even redirect it at the last minute if needed. Appreciate the feedback and ideas.