Thank you for this info. My issue is now solved. I was able to perform my serverside filter logic and now everything is great.
FYI - I'm the same guy (username: jremi) that you helped related to the sharing sessions plugin. I was asking you about if using the cross storage solution would work for cross domain cookies.
Thanks again for your help. I really appreciate your assistance.
added a new filter:register.build that allows adding a data.captcha html value to the register template data, also made its response add an ?error=message param to the /register url
modified hook filter:register.check arguments
added few utils functions, check them out, they're cool
minor other fixes