@AC: Aussie Post
I'll put in a 'me too' with a bit more info...
I understand you can blame the delivery contractors (within aus-post) for that. They are able to hand off parcels to posties that are on the large side but still within arbitrary constraints. So the postie can a) carry around large parcels in their bike sack and risk it not being delivered, or b) just deliver the card.
One of the posties on my route knows I'm home so often times will deliver the parcel. The other one doesn't :(