When I was delivering a cake recently the reception site coordinator came over and said "You're the second cake person we've had in here today."
I asked him what he meant, and he told me that they were having two events there that day, one in the other room. The baker for the other event had arrived and started setting up the cake for the other room in the room I was in. They were almost done when the coordinator saw them and told them that they were in the wrong room. So they had to undo the entire setup and move it next door.
Now why they would do that, I have no idea. Considering that the table had napkins with the names of my clients on it, you think they'd have figured out that it wasn't where they were supposed to be.
So when you call ahead of time to check on delivery, maybe you should check to see how many other events are being held in the same place that day. And pay attention when you get there to make sure you're setting up the right cake in the right place. Read the napkins, it could help.