If your ability to defend from corporate espionage depends on the Bad Guys not asking you questions, then you're not defending yourself from corporate espionage

If your ability to defend from corporate espionage depends on the Bad Guys not asking you questions, then you're not defending yourself from corporate espionage. The onus is certainly on the engineer to distinguish between information they can divulge and that which they would need clearance for. You can't ask the good guy to not ask questions by stating that questions are what bad guys use to trick by social engineering. Your argument is inverting the burden of responsibility. It's not OPs job to protect your IP, it's yours. You can't ask them to not ask any questions in case that a questionee was in possession of IP and susceptible to social engineering.