I've heard a lot of similar stories, but never had that problem myself. I've been really lucky to have shippers who are very up front about the schedule and such. I'm sorry to hear about your experience.
A good horseman doesn't have to tell anyone...the horse already knows.
This happened to me, shipping horse from NE to midwest, too! Unfortunately, some down trees caused shipper to have to take more back roads, which resulted in a huge delay. An approximately 20 hour trip turned into 36 hours, and my horse never got off the trailer (they had 2 drivers).
They also didn't call me to tell me that she wouldn't be there the day we expected. I was not impressed, but she made it safely -- just quite tired!