Perhaps the delivery persons are following orders. They're not paid enough to have initiative, and may in fact get disciplined for showing it.
But it also reminds me of the description of an empty rubbish receptacle on a pavement, surrounded by a ring of the rubbish that should have been in it. When I first read that, I thought mebbe the rubbish-bearing oiks couldn't throw straight, but it might have been just a "stuff you" comment by said oiks. Or an outdoor Tracy Emin installation.