[dkdbejwi383]

You'd still get a note off event, which would then trigger the release part of the envelope or whatever.

[dhosek]

Sustain pedal. Not sure how it’s implemented in midi, but that’s one way to have more than ten notes playing at once. (There’s also four-hand duets and the rare but not non-existent play two adjacent white keys with one finger technique.)

[b3orn]

Yeah, but ideally you'd check if the note is actually playing as part of handling note off.