Most garage owners do not want staff, customers or suppliers finding out that a sale is being considered. Public marketing can be anonymous, and identifying details are only released in stages as interest becomes credible.
Interested parties are registered, placed under confidentiality where appropriate and asked sensible qualification questions covering background, timing, funding position and fit, before sensitive information is released. The result is fewer casual enquiries and more serious conversations, so your time goes on buyers who can genuinely proceed.