According to the federal financial crime unit of the Belgian police 43 mules were arrested in Belgium in 2008. As journalists don't really understand what a mule is, they made a headline as if only 230.000 Euro was won by the criminals. This is not reading the real numbers and facts.
In total the mules send about 230.000 Euro from Belgian hacked bankaccounts to the criminal gangs. They wanted to send 383.215 euro but they were blocked by the banks, cardservices and police to do so. The police found about 154.083 Euro that was given back to the rightful owners. So, this means that there is still a time-lapse that is too big between the hacking of the account and the sending of the information to the mules and the transfers done by the mules and especially the last one (to the crimegangs).
The mules that were recruted in Belgium were really poor and marginals. Maybe this explains some of the time-lapses. You have to know something about the workings of computers and banks and moneytransfer services and have some social capabilities to not being caught.
If you recruit monkeys as mules you are a mule and will get caught. :)
This means that over time - as with the online crimebusiness - the mulebusiness will become professionalised. The crisis gives them every opportunity.