Interesting ideas but several drawbacks most notably a) If you have some set of heuristics that serve as a proxy for information (in this case "humanness") then

Interesting ideas but several drawbacks most notably a) If you have some set of heuristics that serve as a proxy for information (in this case "humanness") then people can easily optimize on the proxy and win and b) the code would be running on the client-side and as a result super hackable