COOKIE name restricted?... CI_Input::_clean_input_keys

[eluser]Ajaxboy[/eluser]
the page just dies "Disallowed Key Characters"

so as part of my general security procedures I encrypt cookie names that store user_id (and the id itself) for the session for security purposes.., but CI wont allow to name cookies with any special characters and not even in the cookie content!!! - with the sanitation.. , so.. maybe it should allowed special characters in cookies?, are there are risks I am not aware of for allowing them?, and won't let me get past this point, isn't this a bit intrusive?.. (please note that I am not using the CI_Session to store any data, It just a simple cookie that I am setting on my own class