My wife’s been tested here in FL several times. This was done at the local hospital as part of their COVID precautions pre-treatment, not a mass-testing site. So the procedure we’ve had may not be representative. But even so, these procedures are definitely ad hoc stuff they invented just a couple months ago. And it is a drive-up & stay in the car process.
We’re pre-registered for the test by the hospital scheduling department. When we show up they have a small sheet of pre-printed barcodes with her name, birthday, etc. on them. Same as when anyone gets any other treatment at that hospital. The sample takers shows her the sheet, asks her to confirm her name & birthday are correct, then sticks one of the stickers onto the sample tube. Then the swab goes up the nose, into the tube, and the cap is installed. Kinda hard to screw that part up.
I suppose a testee who couldn’t read, couldn’t speak much English, or just had a really sloppy mind could just glance at the papers, say “yeah, yeah”, and end up with somebody else’s sticker on their sample. But that’s what it would take. And that goof would probably be discovered when the person whose sticker it really was showed up and the staff said “Wait a minute, we already have your sample. Oops!”
Regardless of the quality or lack of the part I just described, what happens later is anyone’s guess. The samples need to be logged, tested, and the results sent out somehow. All those admin processes can have glitches too.