Problem...

Hello, I don't know if this is the right group for it, but I'm posting it here anyway... I have an online browser based gaming site (not displaying the URL for possible advertising rules in this group, since it's not really relevant) , and I got a little problem here... My visitors try to be online as much as possible, logged in... they have to update things, by hand... now, visitors get smarter and smarters, and while they are sleeping, they have scripts/macro's running to update their information. Now my problem: is there ANY way I could detect that macro? I was thinking of generating a number and displaying it in an image, but that will cost the player a lot of time. I was also thinking of automatically logging out once in the 30 minutes, but that will cause a lot of irritation too... Any suggestions? Thanks in advance, Leon Mergen