A "Human" makes a huge difference
When dealing with any company or just a small business, isn't nicer to actually have dealings with a real person versus a machine? Now think of your haunt, it's basically the same thing, a business seeing real , live customers.
A tour guide listens, learns what his group might be anticipating, expecting, then he may be able to modify some small , certain things along their travels to make some of them happen. It really doesnot take all that much effort to scare, distract or entertain many people, if they are in the hands and under the direct influence of another real, live person.