Bluffing works until the follow-up question. There’s always a follow-up question.

Faking knowledge buys you about one exchange. The follow up question is the part nobody plans for, and it arrives almost every time, because interested people naturally ask a second thing. Getting caught there costs more than the original admission would have. Saying you do not know is boring and it ends nothing.

Try the plain version this week: not sure, I would have to check. Then actually check, and bring it back to them, which is where the credibility comes from.