With a QD code tracking the test you don't worry about fake tests, and you can compare test results against product claims by manufacturer to ensure test reliability. You can keep upgrading to tests that show the best proven reliability in actual use.

The more test results, the more reliable any models are for analysis.

Edit added - QDX HealthID could have contact tracking built into it, but I don't know that for a fact. I don't see any reason it couldn't. The cellphone screen we saw was the User screen. We have not seen the Test Giver screen.