One solution for this sort of problem is fully auditted code running on a server hosted by a third-party in a controlled and monitored environment
What third-party sets that up? Do you trust that they didn't install a back door? Who audits it? Do you trust them?
You're still left trusting somebody not to cheat.
Indeed - to do it securely would cost a load. You're having to look at a reputable large company hosting with live video feed of the hosting area, secured and logged access, insurance in place for security breeches etc. End result being greatly enhanced confidence for investors of fair-play (but not zero risk) with new CP for yourself at a massive cost and with serious delays any time an update is needed (delays both to get access and for changes to be audited).
Auditing would have to be done live on-site by multiple independent parties etc.
A whole lot of effort when there's zero reason for you to do it - but without the servers in a controlled environment there's essentially no way to do it. Which is why I think the idea is just a waste of time.