I have C# from a school module from 7 years ago on my resume. I wouldn't be able to answer many interview questions about it but I would be read to work in C# after a few hours of brushing up my skills.
I also have 5 years of software engineering in a FAANG working mostly on Java.
But I guess you wouldn't hire me then.
It's fair to ask what level of proficiency the person has and skip the questions you were planning to ask if they answer like me, but it would be stupid to actively try to trap people.
I'm not trying to trap anyone. I would ask you about C#, you'd say "that was seven years ago, I don't remember the details" and we'd move on. I'm looking for someone who starts making up things about C# assuming that's what I want to hear.
That's the kind of person I'm trying to avoid. Someone who isn't honest about their skills.
I also have 5 years of software engineering in a FAANG working mostly on Java.
But I guess you wouldn't hire me then.
It's fair to ask what level of proficiency the person has and skip the questions you were planning to ask if they answer like me, but it would be stupid to actively try to trap people.