Red Flag laws likely being extended to allow pre-emptive ID of anyone using "violent rhetoric" online (this will have the broadest possible umbrella definitions - basically anything not enthusiastically progressive of mind), and they'll just demand full access to user databases to track individuals via their connection history etc (they'll already have all that shit from the NSA anyway, this just gives them direct legal avenues of attack/action with a usable paper-trail).

Of course, any serious rhetoric could easily be supplied by the interested agency itself to trigger the initial raid.
As with all their modern cyber techniques it's all super-untrustworthy and sketchy, lacking any real investigative rigor, which is why they need the supporting laws to allow pinning the broadest possible interpretation of a Red Flag on anyone (or any platform) they just don't like with no real recourse.