Premium users have the ability to completely disable mod security on their account via cPanel - even though x10hosting discourage it.
For free-hosting x10hosting has a customized web server setup that does not allow for the same cPanel functionality to disable mod security - x10hosting also decided it would not be a good idea to allow free-hosting users to disable it - as it is used to not only protect against inbound malicious attacks but to prevent outbound abuse also - Unfortunately free-hosting still gets abusive signups - and allowing them to disable something that prevents their malicious actions would not be in x10hosting best interest