No, I don't think that's reasonable. Any outside resource ranges from pen and paper, a basic calculator to all the books you have, the Internet, ChatGPT and the help of other people.

I would say that the only thing that should be assumed implicitly is that it's forbidden to use the help of other people. Anything else should be explicitly laid out.

Having said that if some rule is not clear or evident then the interviewee should ask. And they should never be dishonest.