Threats to IDS/IPS deployments

I'm performing a risk assessment for a commercial IPS deployment at my place of work. The scope of the assessment is limited to how we implemented and deployed the product - not how the product works. Some areas that I will be reviewing include authentication and authorization to the sensors and management systems, backup of data and configuration settings, hardening of the sensors/systems, and best practices such as testing signatures prior to installation into production. I apologize if this is the wrong place to post. I'm looking for input from this list as to current threats against IPS/IDS installations as well as other areas to review during my assessment. Thanks!

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