Is it a medically and scientifically sound strategy to somehow mark the unvaccinated so that vaccinated people can avoid them?

Some kind of way to identify them in public, like something that they could wear on their person that was really visible.

Everyone vaccinated would know who they are and what they're about, and how to avoid them and not do business with them.

It would be really easy to round them up i and we have to go into a full unvaccinated quarantine too, as law enforcement could just drive around and spot them

Lots of countries are going into all unvaccinated quarantines too, so we'd be able to spot them if they went outside