Yes this is true but since somehow traders have an higher chance of getting right predictions then we might just think it's a trader while still not disrupting the fact that they might be one hell of a gambler getting such predictions right.
Am still not convinced (and I don't think I'll ever will) that traders have some advantage on this game over other players. If this was true then they can make a fortune by trading on trading platforms.
Besides, again, within 15 or 30 seconds the difference between the start price and the end price will most likely be few cents and since the games uses three different exchanges am sure the exchange rate will be higher on some of them and lower on the others.