Here's a primer on contact tracing (you'll note there is a confidentiality aspect- no names are included as part of the traceback): https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/contact-tracing.html
Also estimated only 40% of symptomatic COVID-19 case contacts need to be identified and quarantined to manage spread, your examples are unlikely to constitute >60% of a symptomatic person's contacts: https://www.statnews.com/2020/05/29/contact-tracing-can-it-help-avoid-more-lockdowns/