Maybe you could send them a return message. They wrote "Smiling doesn't hurt"? Your message could be "Neither does leaving me alone" (with a tongue-in-cheek face). ;-P
Seriously, that's weird ... and possibly a bit freaky. Think about it: whoever wrote that assumes that you don't smile. How do they know? Do they watch your doorbell camera? (That's the freaky bit). I don't know if it's even possible, but Amazon and other Big Tech companies are well-known for collecting all kinds of data about their customers. (And if I was paranoid, I'd go down to the basement and hide until after the Amazonalypse).