due to subversion of the website by the Russian mafia, who had inserted RC material. In the same discussion Bill Henson's website, despite the PG rating given to his photographs by the same body, appeared on the blocklist due to a technical error according to Stephen Conroy The ACMA has since released a statement claiming the technical error was a "computer system caching error" and further stated "found that this is the only URL where a caching error resulting in the URL being incorrectly added to the list." Live filtering trials The government has committed to trials of the mandatory web filter before implementation. On 28 July 2008, an Australian Communications & Media Authority report entitled "Closed Environment Testing of ISP-Level Internet Content Filtering" showed performance and accuracy problems with the six unnamed ISP-based filters trialled. EFA analysis of the report showed that: One filter caused a 22% drop in speed even when it was not performing filtering; Only one of the six filters had an acceptable level of performance (a drop of 2% in a laboratory trial), the others causing drops in speed of between 21% and 86%; The most accurate filters were often the slowest; All filters tested had problems with under-censoring, allowing access to between 2% and 13% of material that they should have censored; and All filters tested had serious problems with over-censoring, wrongly censoring access to between 1.3% and 7.8% of the websites tested. The trial tested speed on a simple "black listed or not" basis for all simulated clients on all systems, yet the report outlines the ability of the filters to provide customised filtering to each client (as would be required by the two levels of filtering which ACMA is proposing) which would significantly impact test results. In November 2008, the Government hired Melbourne company ENEX TestLab, an RMIT spin-off, to design a live pilot test on a real network. In this trial, in which several ISPs have expressed an interest, 10,000 blocklisted "unwanted" websites would be censored in addition to 1,300 websites identified by ACMA. As an incentive for participation, the department states that participating ISPs "will be recognised for their participation in the Pilot. This recognition will strengthen their brand image with the community". These ISPs will also be allowed to keep any software and hardware purchased by the government for the trial. The trial may include some ability to censor