Someone betting Taleb-style would have an edge over someone directly betting on Silver's forecast numbers, but technically that's not arbitrage -- arbitrage in

Someone betting Taleb-style would have an edge over someone directly betting on Silver's forecast numbers, but technically that's not arbitrage -- arbitrage in the sense of the article means a strategy with guaranteed return, not just very probable. Is that right? So my impression is that this is an argument about words, where traders mean 'arbitrage' more broadly.