I wouldn't doubt it in the least. Indymedia, DUh, and other sites have been hosting disruption campaigns on FR. I know that I have read articles where some "concerned citizens" tell a reporter about how "FReepers" are "using the internet" to gather to arrange a counter protest to this or that. Like no other people use the internet to meet up.
I do not see FR as an activist site. Most of the discussions seem to be commentary on news reports and personal observations (some are vanities, some contain more news details from first hand accounts or detailed research). Activism threads appear under a seperate heading on the sidebar.
FReepers get called out in the biased press for "FReeping" inline polls yet I have also seen confessions from people who ISLAMmed a poll or DUped the media by DUmping more votes on a poll. We are the only ones who get called out on it.
We could retaliate by searching the web for LA Times and Washington Post reprints on leftist sites but why bother. We can do more good by defunding leftist activist organizations that use the 501c3 tax dodge. Some cases are now coming to court. Report things like the Rock The Vote call to vote NO on California's Prop 54. 501c3s are not permitted to tell people what/who to vote for/against. Tell the IRS and FEC and let them do the work.
Defund the left. Fight election fraud. Jail seditious rioting protestors (anarchists are admitedly anti-government).