How do you test troubleshooting skills when interviewing DevOps / SREs? Do you spin up live environments; do you ask questions; what types of questions; do you ask them to script; whiteboard or using a tool; what tools do yo use?
It might be better to ask a behavioral question like: "Tell me about a problem you once fixed that was difficult to reproduce. How did you think through the possible causes, what tools did you use to gather information, etc.". Then ask followup questions to get more details, e.g., ask more about how they used their tools. If they're bullshitting (for example, they only had only a minor role in fixing the incident), it will be hard for them to provide plausible details as you dig deeper.
If they answer this question to your satisfaction, you could then ask them to show how they'd use certain tools, but they might have been using proprietary tools at their previous jobs (e.g., if they worked for a huge company like Google) and may be unfamiliar with the tools you're using. You wouldn't want to turn down a good candidate just because they're unfamiliar with the specific tools that you're using.