Actually I don't think this is illegal. They aren't brokers, or otherwise filling orders, so they can't "front-run" per se. Also, I don't believe front-running

Actually I don't think this is illegal. They aren't brokers, or otherwise filling orders, so they can't "front-run" per se. Also, I don't believe front-running is illegal in commodities markets, as they aren't regulated like equity markets.