I thought the Boléro was already in public domain for many years, but I just heard it only entered today.
Now I wonder if LOGH's production did know that back in 1988... I suppose they could have though that all the European classical repertoire was free.

It depends on the region. Works enter the public domain in certain areas depending on the local laws. If I'm correct, in Japan the Boléro would have entered public domain around 1978 because works are only protected for 50 years over there (it's currently being extended to 70 years with the Trans-Pacific Partnership negotiations). The United States has been having issues with Disney lobbying continually to extend it's protection of intellectual property (IP) so they can keep having Mickey Mouse and their other properties covered by IP laws

I heard about the Disney issue, but I imagined that difference between local laws applied according to the nationality of the work, not the country in which they are used.

That means that a work from country A (whose laws protect only for 50 years) could be in public domain in his homeland, but still protected in country B (whose laws protect for 70 years)... that's very strange ^^

But I'm sure you're right, I would not be surprised if these kind of strange cases are possible.

EDIT: thinking about it, this is not so strange...