Of course that would only make sense if the prize if big enough, but yeh, even CAPTCHA can be solved automatically (either with script if weak CAPTCHA or with a service that pays humans a very small amount for solving the CAPTCHAs you give them.)
Even faucets on sites like PrimeDice and bustabit are being abused by scripts like that. So if someone could win some serious money on your game, for sure people will make a script like that.
edit: just to be clear... I like new ideas Just that almost all "skill games" will be easily abused
Ok, thanks for your comment! I will think further on this idea or others