I think one way would be to disable pasting text into chat (or disable it all together). But then they'll probably use macro or something, but I'm pretty sure it's illegal so you can ban them like you do now (haven't read ToS but that's the case for most MMOs). Of course it won't get rid of every bots but a majority of them. Anyway why would you need to paste something in the chat, I don't think that's used a lot so it won't be missed by a lot of players. Another way would be to enter a captcha when you login for the first time, it would definitely slow them but I know some players don't like this.

Unfortunately, there's no easy way to eradicate this threat that plagues every F2P MMOs. I do hope we get rid of them someday.

I'm sorry to tell you, but this suggestion has some serious flaws. TLDR; #1 Bots don't copy/paste text. Removing that functionality from chat doesn't affect any botting at all. #2 Players use copy/paste functions for faster communication.

Not a solution. I work in IT, this is not how you do it. Please, if you never wrote a script in your life, I humbly ask you to please, don't make a suggestion about something that involves IT knowledge about botting and such. Typing the text for a bot is faster, easier to script, offers greater flexibility and is more reliable. Thus, it is easy to see that bots don't use the copy/paste function, that's actually slower runtime. Most if all scripts would type the text for it doesn't rely on OS functions.

Then there is the point that players - unlike bots - USE the copy/paste function for communication. So, could we please not suggest removing features just because someone thinks it is related to something that is not meanwhile making communication harder for everyone?