Its all just about move your head and think.
Contact via jsp or confirm „ingame” with character name would be enough.

Or something like „remember to verify other trader”.

If someone Got scammed because he believed in bnet chat mumble that means hes just stupid.

We will not be adding any "required" reading popups or prompts on the site. No one reads them anyway, just like when installing games or software. You always skip to the bottom click accept and go on your way. While I understand your intent with this suggestion, it will not provide the benefit. It will only serve as another annoying popup / forced to accept agreement that users will ignore and blindly click ok.