It's always been the unofficially accepted way things are done in the music business. Short samples are tolerated, but some people are sensitive and try to sue and then I believe it can go either way depending on the details. If you lose, you'll have to license it.

Caveat Emptor: I am a software engineer who loves music and about 20 years ago I read a book about how the music biz works. (spoiler: it was mostly quite ugly behind the scenes!)