The language in that email sounds formulaic. Wonder if the buyer sends that same email every time.

I've seen that kind of 'internet blackmail' before, where someone threatens to destroy your reputation on Yelp or something like that. Honestly, just keep everything documented and tell the buyer politely that you're sorry but you can't be held liable for any damage that happens in transit.

When I bought my first pinball two years ago, even though I was green as anything, I still wouldn't have expected an issue with the game after I got it home to be the responsibility of the seller.