[Bush2000]

They've been filing lawsuits against end users for years, with little effect.

Maybe if you consider criminal convictions for copyright infingement a "little effect".

Microsoft Software Pirate Given 3 Years in the Slammer
Industry toasts first conviction under No Electronic Theft Act
Record jail sentence in piracy case
Former Austinite Sentenced in Software Piracy Scheme

There are too many examples to list. Go to bsa.org. Criminal convictions for piracy have become commonplace.

[HiTech RedNeck]

High profile abusers, businesses, reselling pirates. The private home user has infinitely more to fear his door bashed down for child porn, than for ripped off software.

[MTOrlando]

Maybe if you consider criminal convictions for copyright infingement a "little effect".

All of those convictions have had no measurable effect on reducing the number of "systems builders" who load pirated software. Microsoft's own actions prove that what they've been doing doesn't work - otherwise, there would be no need for this amnesty program.