Everybody likes money. Everybody likes money without having to work right away, too. So let’s say that your e-employer says he’ll pay you an advance on your paycheck. Cool, right? You get the check, deposit it, and there’s no problem. Until your employer says he needs the money back because something didn’t go quite right. So you send him the money, expecting the advance payment fairly soon.
However, the issue with this is that the initial payment was a fake check. Your bank wouldn’t know right away, so it may seem like a proper deposit for a day or two. When you send the money back to the scammer, well… All he has to do is cash it at his local grocery store, and you’re the one left answering to your bank.