IT is always responsible of the production platform. As such it is controlling the quality of the rules deployed to the servers. As the simplest process you can have the business users maintaining the rules within the web based BRMS component and even deploy to a test server to do some simulation testing and what-if analysis. Once the rule execution set is ready for deployment to production, IT can create baseline, extract the rule set from the rule repository and then apply some non-regression testing suite to verify that the rules are still working as expected. This is a good timing also to verify that any changes done at the data model level (logical or physical models) are not impacting existing rules.
The following diagram illustrates the different activities per role, I can easily imagines as a standard maintenance process:
So IT is still responsible of production quality control, version control, software components integrity, production server monitoring and management and nothing will change in close future.