What? How would I ensure that the race is actually being live telecast? It may always be a recorded one, where results are already known to you. How this type of a setup be provably fair?
Ok so we tell you Mice racing live and that's your first reaction? You must be fun at parties
Nevertheless the concern is real and it is indeed something that could be triggered in several ways.
Best would be for OP to implant a live chat during the race, where people could ask you to write a word on a paper then you show paper on the camera and it would prove it's live recording.