If the mechanic is walking past her and talking to the guy waiting for her in his car outside, then I think you’ve got a point.

I’ve done what you’re describing for a bunch of female friends / partners. A lift back from the MOT means arriving in a different car. Even if I do get out of the car (which I probably wouldn’t) I’m not even engaging in the conversation because it’s nothing to do with me.

Now…buying cars with a friend. There’s a situation which can go very wrong!