Concern trolling in the false flag political operation sense is a thing that happened

An example of this occurred in 2006 when Tad Furtado, a staffer for then-Congressman Charles Bass (R-NH), was caught posing as a "concerned" supporter of Bass' opponent, Democrat Paul Hodes, on several liberal New Hampshire blogs, using the pseudonyms "IndieNH" or "IndyNH". "IndyNH" expressed concern that Democrats might just be wasting their time or money on Hodes, because Bass was unbeatable.[37][38] Hodes eventually won the election.