Sometimes leaflet distribution is contracted not to the Royal Mail, but to private companies. Many firms do this. There is no chance of specifying individual houses that are not to be delivered to.
They don't hand them out, they post them through letterboxes. As I say, many companies do this. takeaways being quite common.
I can't believe nobody has ever heard of this practice. I sometimes feel like I'm on another planet in here....
Did you all believe that EVERY flyer that ever comes through your letter box was delivered by the postman?