[pokergrader]

Its pretty much impossible. A good programmer can solve anything the clients throw at them.

Now that computers are fast enough to screen scrape and figure things out quickly, there is no reasonable obfuscation the poker room clients can do to solve the problem if they want to keep things usable and comfortable for the regular players.

Captchas can inhibit bots, but you can just hire 1 person for $6/hour to type them in over 15 bots, so they really aren't that useful (there are also software programs to captchas, but much like this exact situation, it is a lot easier to create something to foil than it is to prevent it, so I will use the worst case scenario for a bot user). It is sort of hard to make bots that are winning, but once they exist and can handle the current software, it is nearly impossible to detect them via software if the bot writer is smart enough.