Since hiding them any other way breaks the application - I set the params class to "display:none" within the template CSS to hide them from the front-end.
Not exactly an elegant solution, but the best I could come up with.
I have the same problem I installed joomla 2.5.9 and the component CB 1.9 when I update profile in the frontend "Contact Info" the user table field params get like this:
{"0":"{\"admin_style\""\",\"admin_language\""\",\"language\""\",\"editor\""\",\"helpsite\""\",\"timezone\""\"}"}
But if I update in the backend the params field come back to :{"admin_style":"","admin_language":"","language":"","editor":"","helpsite":"","timezone":""}
There is something that I can configure or it's a bug?