

Tracking smartphone users is a billion dollar industry, and it’s not that hard to figure out where a user is working if you have their location data and a million other data points from their phone usage. That doesn’t necessarily mean that this data is easily accessible to every employer, but it’s absolutely possible to know someone’s work history with reasonable certainty without government databases.
The thing is, they don’t need irrefutable evidence to toss out your resume, or at least be suspicious enough about it to ask you what you did in a given period; and if they already paid for this data, they might as well verify your answer as well.