KNTV - Groupon is in hot water with a Washington, D.C.-based group called "Morality in Media" for offering discounted tours of pornography website Kink.com's fortress-like San Francisco headquarters.
Kink.com films fetish porn movies at the former National Guard Armory at 14th and Mission streets.
The structure is large, imposing and popular.
Groupon reportedly sold more than 1,000 coupons for tours of the building according to the San Francisco examiner.
Kink.com founder Peter Acworth bought the Armory, vacant since 1976, in 2006 for $14.5 million.
Morality in Media is not a fan of the Web site's "sadomasochistic torture and rape pornography," according to a statement.
The tours are "disguised" as history, according to the group, which was further incensed by the idea that tour-takers could "glimpse a live filming" on their tour.