A: It can happen, but it is not a routine step in every marriage green card case. USCIS investigators may conduct a home or site visit when the agency believes additional verification is needed. If officers contact you, verify who they are, answer truthfully, and do not guess. A case that has reached an investigative stage should be taken seriously, especially if USCIS is trying to resolve inconsistencies in the record. If a visit happens, answer from what you actually know instead of guessing.
Sources: USCIS Fraud Detection and National Security Directorate: https://www.uscis.gov/about-us/organization/directorates-and-program-offices/fraud-detection-and-national-security-directorate