People often ask me this - some even complain to the SEI that there isn't a "question bank" available that every LA is supposed to ask. Unfortunately, this betrays a lack of understanding about how the CMMI, and SCAMPI, is used.
In SCAMPI, process performance is verified through a number of means, with interviews being one of them. There are also other means - documents, presentations, surveys, and others. SCAMPI finds practices to be strong or weak based on the combination of available evidence. Depending on the organization, we may not even ask a question about a certain practice if other evidence is available.
The questions we ask also are best if they're tailored to the organization's situation. For instance, if it's a company that makes microprocessors, questions about software may be invalid.
Another instance is the need to tailor questions to fit the local culture. If I'm appraising a small, agile organization I'm not going to fill my questions with references to "Change Control Boards," governance infrastructure," "SEPGs" and other words or phrases typical at large companies. If it's a huge DOD contractor, I'm not going to talk about "sprints," "jolt cola" or skateboards either!
I do have a database of questions I ask, and the list is always growing just like I am always learning.