Our center recently pushed our start time forward to 9:30 (9 on Mondays). My first ground delivery stop is Walmart. The receiver likes to take her break between 9:45 and 10. She could care less that our start time changed and will take her break unless I call her to let her know that I am on my way.
Why do I do this? It is much easier for me if I get rid of Walmart first rather than having to work around it and go back. Yes, I could go there, knock on the door, be told she is on break, scan the air and leave a delivery notice, but it is so much easier to call her just before I leave the bldg.
If it were my area and I knew that I had to have someone meet me at a delivery point I would most certainly call them ahead of time.