I don't see them charging a customer another $100 for wrong parts.
It all depends though, if like ICE, a mechanic can tinker and replace every part on your car in effort to fix an issue. However, they get the best deal since their hourly rate increases as well as replaced parts. I had a GTI back in the day, would stall on every shift, took it to a German mechanic who raced them, he tinkered, advanced the timing, and said I go most of it out and your bill is $450. I got frustrated... never was satisfied with any results from outside mechanics, took the car home and raced it up and down my 1/4 mile driveway to build data. Within 15 minutes of building and analyzing the data I discovered it was the rubber boot that had dryrot cracks between the mass air flow sensor and the airbox. Was getting more air on shifts which the engine rotated and opened the cracks even more. The part was $20 for the boot and say 30 mins for my time, total cost of this repair by the mechanic should have only been $70 at most. I went back to inform the mechanic, hopefully so he can be more efficient and better with his diagnosis, he go's ohhh so that's what it was. I paused and was in my mind ready to get some sort of refund... NOTHING. If I was a mechanic I would have a guilty conscience for taking some kids money in that fashion.
So my point being, if it was Tesla's mistake of bringing a fuse when they should have brought a PEM, well they may charge you for that. However if they brought the wrong 1.5 PEM for your 2.5 Roadster, had to run back to pick up the 2.5 PEM, I suspect they wouldn't charge you.