It must have been a sub or something that didn't know about the dogs.
Though with them being mail carriers, they should know better.... sheesh!
I know ours will leave boxes on our front steps, in the Explorer that is left out front (no one is driving it right now, since we got C a different car) or if it's big, in the barn. But no one would ever open the door and leave it in the house! Some of them have seen Mr Poop!

He's darn near a celebrity downtown with the garbage man and cable/telephone guys!