[Kaius]

Its a question of tolerances, if they break when someone stands on them they there is a decent chance they will break when you sit on them, or sit down too fast, or sit on them on uneven ground that distributes slightly too much weight to one leg, or they have been in the sun too long and have become brittle.

I'm a relatively tall guy and am wary sitting on these, standing on them would be certain failure. They are essentially cheap trash that will spend ~12 months looking like a chair and 500 years looking like a broken chair in a landfill.