From a CVB person who wanted to be anonymous but still share a lesson learned:
Needless to say, we couldn’t make reservations in the contracted hotels since the rooms were already occupied. We scrambled and got the client sleeping rooms in the suburbs, but the group then had to pay for shuttles. The hotels downtown did not achieve even half of what they were supposed to . Lawsuits were threatened. After the convention, the planner quit and the exec. dir. was fired.
Lesson learned: Always verify that if you are going to move something, all parties are contacted to make sure it will work. Never assume anything.
Do you have any lessons learned the hard way? If so, please drop me a line or leave a note in the comments below. I'd be glad to share your stories (anonymously, if you like) in the hopes that someone else won't have to learn the hard way.