Regarding if they are a ponzi: btc-arbs admin was tracked down and now he cant be so sure about his and his family security, if someone else is risking to get into this position let them. It will be even easier to track down Bitcoin-trader.
In my country some startups stay in shade as long as they can, because otherwhise goverment will milk them with their crazy taxes.
But stayin anonymous for customers is no relation to this.