I talked to two different Tesla reps about previously repaired cars. I asked about two specific cars. With the first car, they told me it was a 'sideswipe type of accident' and that no body panels were replaced, which suggests to me body filler. Did not know who did the repairs. On the other one they said that Tesla replaced the front bumper cover. (It was a lease return). They said they did not have copies of estimates or damage costs. I asked how they know the repairs were done to Tesla specs if Tesla did not do them, I was told it's because shops that work on Teslas are certified to do the work. I asked if there was any warranty on the work and was told the 4/50k warranty was bumper to bumper and would cover the repairs. Which is weird - with traditional cars, the body shop guarantees the repairs, not the used car re-seller.
I ran a Carfax on the car with the bumper repair and it came up clean. Yet I got a pretty good discount for its "previously repaired: status. I think it was worth it. I would not have bought a previously repaired car with panel damage, or anything more substantial than a bumper cover. And if/when it comes to resale time, the car can be sold honestly with no reported accidents.