i dont think captchas will do anything.where/when would u place one?after login? isnt usefull i mean u think someone would care if he has to put in a captcha before using his bots? i dont think so.after each roll/bet? well noone would do this
u can also track the number of players loggin in.i mean if suddenly 10+ players login at the same time theres something goin on.also can u tell if its always the same bot accounts? because u need to top of every new account before u can play,so for me it would be less hassle using same accounts over and over