You can then ask if they could show a random internal document that they worked on. This depends on the role. For example, an engineer might have an RFC, a product manager some reports or status updates on the team's progress, and a designer the outline of feature proposal.

If the content includes sensible data you always ask them to strip-out references, names, or numbers.

That is going to be a non-starter for a lot of prospects. While yes, we can say that we are stripping out sensitive data this still feels sketchy.