There's no point in arguing the pay to play FO topic again for a single pilot cargo operation.

It is allowed per a company Ops Spec, and yes it's looked down upon in the US. However, that doesn't matter because most of these guys are from a country without a GA industry and this is how they get the time to go to their national airline. It is not only accepted, they are funneled through the program by the airline. I told the two Americans that came through our base (for 100 hours each instead of the usual 500+) flat out that the time is looked down upon. They knew it, but decided to waste their money anyway because it was 1/4 the price of renting a twin.