Captcha would be either pointless or detrimental to the game. If you made a captcha for the login sequence then the *** writers would just scrape the captcha and present it to the botter at login time so they can type it in and then the *** takes over. At best this means that the *** does't autologin after server reset.

Or you could present a captcha at random intervals in the game which would drive human players nuts.

As for the *** writers being amateurs, how many of them do you know and how much do you know about programming?

If Evony was smart they would be asking what is causing people to *** and then find a way to capitalize on that deficiency either through some sort of cents program or eliminating the benefits of the ***.