It doesn’t matter without scope. Are we looking at a database of SSNs? tax records? A sign in log? The social security number database might require uniques in some way, but tax records could be the same person over multiple years. A sign in gives a unique identifier but you could be signing in every day.

It’s like saying a car VIN shows up multiple times in a database. Where? What database? Was it sold? Tickets? Registered every year?

This is nothing more than a “assume I mean immigrants or tax fraud and get mad!” inflammatory statement with no proof or reason.