"Nonprofit" anti-regulation groups evading transparency by exploiting IRS loopholes

A lot of anti-regulation groups seem to be evading the spirit of the law with the IRS & transparency lately.

Influential nonprofits are supposed to file a yearly return with the IRS to tell us how much money they were given, how much they have, how much money they're spending and who's getting it, and who's running the show & how much they're paid.
Yet...

The global warming inaction Science and Public Policy Institute - formed as a 501(c)(3) nonprofit circa 2007 - has (recently?) had its nonprofit status revoked for not filing any returns with the IRS.

The global warming inaction American Freedom Alliance - already active in 2007, notable last spring for their conference featuring Lord Monckton - still has not filed a return, according to Guidestar.

The Western Tradition Partnership, politically-embedded predecessor and seeming companion 501(c)(4) nonprofit to the all-volunteer, lawsuit-filing, exempt-documents-seeking Western Tradition Institute 501(c)(3), might or might not be a valid nonprofit (its EIN# exists, but Guidestar doesn't recognize it), and does not appear to have filed any returns with the IRS.

Both the Heartland Institute and the Atlas Economic Research Foundation are supporting anti-regulation groups internationally, but are not required to identify these recipients because the recipients aren't within the U.S.
(Plus it's possible that the mighty-well-funded Atlas didn't file a return at all in 2008; that year's filing isn't present on Guidestar or ERI.)
Dec. 8 update: An Atlas staffer pointed me to this page for their 990s and other documentation.

Dec. 8 update II: The don't-price-carbon Breakthrough Institute doesn't appear to even be a 501(c)(3); despite having considerable staff, it's still under the wing of Rockefeller Philanthropy Advisors, which lets it skip filing any Form 990s.

Is this a new strategy, old lessez-faire, or happenstance?

(Here's hoping the Mashey-Deep duo can enlighten us on this.)

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(My own county has issues too - the anti-regulation, science-agnostic "Sierra Environmental Studies Foundation" has given out $65k in math(*)-test-driven scholarships over the last 4+ years, but has never had to file a [non-postcard] return because they keep their expenditures below $25k a year. And the head of the anti-regulation group CABPRO was claiming it was a nonprofit, yet seemingly never filed returns with the IRS; though they've since backtracked from the "nonprofit" claim.)
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Minor edits 2012-01-17