Premium users have the ability to completely disable mod security on their account via cPanel even though we do discourage it.
For free hosting we have a customized web server setup that does not allow for the same cPanel functionality to disable mod security, we also decided it would not be a good idea to allow free users to disable it as we use it to not only protect against inbound malicious attacks but to prevent outbound abuse also. Unfortunately free hosting still gets a fair share of abusive signups so allowing these users to disable something that prevents their malicious actions wouldn't be in our best interest.
We are trying to make modifications to the rules in order to make everyone's scripts compatible with the rule sets. We just need ways to reproduce\see the issue so we can rewrite the rules accordingly. So if someone has an issue we need more information besides that it's not working.
Since implementing our new block lists and mod security rule sets we've seen a drastic reduction in compromised user sites and bot spam which means less suspended users, faster servers, and more time for us to work on other features. Across our network we're blocking thousands of bot requests per second which has on average increased our idle CPU time roughly 30%. As we continue to write rules and get better at blocking all these malicious hack attempts and bots I'm hoping we'll further increase those numbers.