It was probably one of the previous owners, and them changing the badge without disclosing that it's actually a 60 seems to put the bad-faith blame on them.
Having said that, if I was going to drop $40k on a used car, I would certainly have inspected everything... the carfax, title, stickers on the car, maintenance history, with Tesla themselves, etc. Surely one of those would've hinted to the current owner that it's actually a 60!?
There is plenty of "way". Maybe they did mean to give it as a free upgrade bug did not properly document that. Maybe the person updating the badge did not realize that it was not supposed to be unlocked. Why are you jumping to conclusions like this just to give some corporation the benefit of the doubt especially when it in no way excuses them remotely downgrading the vehicle WITH NO WARNING.