I didn't actually know about these stickers and have never seen one. As I said I work for RM part time but am not in deliveries, instead working in distribution in a mail centre dealing with business mail.

Why would you not want your mail left with neighbours? Don't you get on or trust them? All the neighbours near me are older retired people and really nice. We all take parcels in for each other. I would say I never trusted all my neighbours at my other house though and might have considered this scheme.

You would have thought these days though that a sticker wasn't needed. Postmen have to carry their PDA with them and log where they are on them to track their movements, for office logistics and so managers can track where they are, and the PDA could easily store this info and they could just check if it could be left or not when someone isn't in.