Does Macy's tell Gimbel's?

Years ago there was an expression "Does Macy's tell Gimbel's? The statement was about keeping a secret, more so in business than personal. It meant that you do not give away trade secrets or give any advantage to your competitor. I still use that saying. At least once a week I get a solicitor phone call. They ask a wide range of questions from who is your telephone carrier to what model copy machine do you have. If I did not call you, why do you think that I should reveal any information to you? Sometimes the caller thinks they are being slick and pretends that they know me. I have been a manager too long for anyone to pull the wool over my eyes. I try to be polite and not hang up, but sometimes I just have to end the call abruptly. The bottom line is, do not ask me questions that are none of your business.