I have only businesses on my route, but several of my residential courier friends carry a box of dog treats in their trucks. The pooches love it (and them).
One of the best things on the internet is the UPS Dogs Facebook page...always good for a laugh:)
:-) Would imagine when they pull up to deliver, the dogs are there to greet with their tails waggin’ like crazy.
A few years ago a postal delivery person dropped a package off at my door and left a one word note after my Great Dane greeted him, “DOG!”