Ooops! Did I misuse the term huelga.??
Maybe a strike is different in nature in Argentina but they are very common in Mexico and Central America and they do not normally involve violence. Your description of a piquete involving violence and disorder sounds more like a "riot" or "protest" than a strike.
This is my idea of a strike or huelga in which pickets or piquetes participate.
"Toda persona tiene el derecho de celebrar reuniones, manifestaciones, participar en piquetes y presentar peticiones, de manera pacífica y sin armas. "