Have you ever met the part of SLA pointing out limits the user should keep?
Yes, a SLA is an agreement between IT (in its entirety) and the Customers of IT Services. This agreement is a two-way street. The SLA is not just to define the Customer’s expectations (someone will start investigating an Priority 3 Incident within 8 hours of its being reported), but also to define IT’s expectations (the users are expected to report Incidents to the Service Desk when they are aware of Service outages).
This can even be taken to the level of the Customer’s responsibility to ensure that the equipment that IT is expected to support meets a certain minimum standard, or that users are expected to have level of knowledge imparted to them by their departments before being allowed to use IT systems.