When both sides of a marketplace are willing to commit fraud, what can the middleman do? Most likely not much. As long as purchases are not "notarized" or other

When both sides of a marketplace are willing to commit fraud, what can the middleman do? Most likely not much. As long as purchases are not "notarized" or otherwise observed in person by a neutral third party, it is very, very difficult to reliably and fairly police unethical or fraudulent intentions for internet purchases.