Maybe 'neutral' isn't the right word. He has the most to lose if the test isn't fair.

I have plenty of experience in tunnels, but no experience with bikes in tunnels. I know how to make small adjustments to cars to make big # differences. I have to assume that anyone who has a reasonable amount of time with bikes in a tunnel can make small changes that would effect the test greatly. Only another person that has that kind of experience can prevent that from happening.