About a dozen inventors in town for a conference set their patents aflame in front of the U.S. Patent and Trademark Office headquarters Aug. 11 to protest what they called an unfair administrative system for invalidating patents.

The passage of the America Invents Act of 2011, a sweeping overhaul of U.S. patent law, led to the creation of administrative patent reviews as an alternative to the more costly path of challenging patents in federal district court. But patent holders say those proceedings, where anyone can claim a patent is invalid because it’s obvious or not novel, make it too easy for those accused of infringement to get patents invalidated.

Moreover, they say, the patent system now favors alleged infringers, as recent U.S. Supreme Court decisions, changes in the law, and the PTAB have led to the cancellation of numerous issued patents.

Read more at Bloomberg.