That is a leagal question, and the answer will not be valid for all countries. In general avoid leagal questions, because you will not be able to trust any answer given.
That said, sample libraries usage is in general, one of the most difficult leagal questions. That also is the case of lmms' samples.
If in doubt- make your own samples.
This should not start a discussion, because no valid context exists, for a discussion
period.