chicagohh - 2:55 pm on Aug 27, 2012 (gmt 0)

Perjury springs to mind

Filing a DMCA is done in "good faith". That's a lot of wiggle room for a clever person. On the other hand, responding to a DMCA - even a wrongful DMCA - is done "under penalty of perjury". Defending yourself against a DMCA would appear to be more of a risk - especially if you can't prove that you originated the content.