Paine is far from the most dangerous long hike in South America. In fact, it is one of the safest.
Still, chances are you will be frequently wet, miserable and sore. On the less visited north side of the Circuit, evacuation is difficult. Emergency protocols are almost non-existent.
Check this list. Forewarned is forearmed. Trails are often damaged and repair is slow. Take responsibility for your own health & safety.
For some non-hikers Paine is a tourist event, which happens to involve hiking. Be ready to assist rookies if necessary.