How can I trust my fellow competitors to record honest measurements?

Ahhh..the million dollar question! First, you have the option of creating a private Contest (only those you invite may join) or a public Contest (anyone may join). In a private Contest, you'll likely know the people you're competing against and will be better able to hold them accountable. In a public Contest, you may not know the identity of your competitors, which means that you will have to take a leap of faith and trust them.