Most people don't unknowingly wear a mask during their day to day activities. The same can't be said of network proxies.

Nothing better sums up their outdated business model then the fact that this study was done by 'The International Federation of the Phonographic Industry'.

This plan could be even more beneficial for the intelligent criminal. When your IDS picks up probing from an IP used by the cops, you'd get a nice advanced warning to start destroying all the evidence. Compare this to the amount of time you get after they show up at your door with a warrant.