Like any strategy it is not infallible. It is a tool to be used in the right situations. If you have a contrary view of volatility (how much a security will move in a given time, up or down) then this can be helpful. Remember this strategy can be reversed as well, so whether you believe it will not move much, or definitely move a lot, you can engineer it to work for you.

But if you EVER hear anyone say a financial strategy is no risk, they are incorrect at best, and actively lying at worst.

> Are people actually making money this way?

Maybe a couple but most are not. A lot of the quant programmy stuff online seems to be more resume fodder than anything else.

> and not losing any money ever?

That's asking too much. There's always risk outside of pure arbitrage.