I have experience the same thing when in for Tesla service. They have also addressed an issue that was unknown to me. They did this out of good will and there was no charge.
So there was an, unknown to you, issue with your car and they fixed it?
That's what service departments are supposed to do. People really are overwhelmed by the strangest things when it comes to Tesla.
What do you suppose would happen if they knew of an issue, didn't fix it, let you drive off with the vehicle, and then something happened as a result?