If I purchase "The Best Percussion Samples EVER" library (I just made it up)and use a tambourine sample that only plays on beat 2...all fine.
If I make a user track of a tambourine that only plays on beat 2 and give it to others to use in their songs...fine? Perhaps a different kind of fine$?
I don't think playing on beat 2 fits the definition of a sample .. or a library
Most licenses concern the sound set libraries themselves.
These are compiled, defined collections (often dll files).
Once you trigger a 'chunk' of this dll sound set and capture it as audio, that's where I think the line is drawn.
I may have used X synth but I told it how/when to play the sound. This is normally what the license is for. A Performance .. timing, velocity, audio capture, etc .. of said sound.
Otherwise why would anybody agree to the license?
If someone posted a User Track of a single sample from a given synth/library (ie the crash cymbal from drum kit X of the above mentioned 'The Best Percussion Samples EVER' library), I may reconsider the intent, as that could be considered a Sample, not a User Track.
I suppose someone could start sharing actual 'samples' under the guise of UT's, but that is surely not the intent nor the use as far as I have seen.
Edit: It appears I replied to the wrong poster ..
quote was from HearToLearn .. sorry