Easy enough even for a single person to run two accounts and obtain enough karma to flag posts.
And easy enough to vouch an article which will eventually bring it to attention to moderation.
Currently the vouch option doesn't appear until/unless a post moves from [flagged] to [dead].
Your right. I was thinking wrong. The only way to combat a flag is upvoting and even then it’s hard to see the impact since I believe it’s karma weighted.