The Chinese CZ-5B rocket launched last week had no support for controlled re-entry (or other managed demise), and is substantial enough that it can survive re-entry and hit the ground. This is unusual: these days, large launchers execute a planned "safe" re-entry, and crash into a defined area in the ocean. Last year, a launcher of the same type crashed in West Africa, having overflown New York. It's all over the news - where will it crash? (More details). Several decades ago, the US Skylab came down into Western Australia, which was, and is, sparsely inhabited so no damage was caused.
Hypothetically, space junk could crash in my garden and kill my dog. If it did, I would be expecting to instruct my solicitor to seek maximum damages!
But seriously, what are the implications of this? Does the fact that it's specifically a spacecraft make any difference? It's pretty reckless - does that element play a part?
(I'm in the UK. Does that make any difference? Actually the UK isn't under the flight path, so this is even more hypothetical in this case than you probably thought.)
My suspicion is that it would be considered a minor international incident, and China might pay some compensation if it seemed in their interests, and wouldn't if it didn't. It might be considered a more major incident if it hit, say, the Pentagon...