I've been keeping an eye on two accounts that are pretty obviously sock puppets, and are farming (small amounts of) rep off of each other. I believe they are sock puppets because:
The accounts were created on the same day (although that alone isn't definitve)
They participate in an abnormal amount of each other's questions. This might be normal if it were one language, but they participate in a wide variety of language tags; almost seemingly at random. I noticed them originally in
[clojure], and they've since moved onto
[elm]and a few other places.
I flagged one of the questions, and a mod accepted the flag as helpful, but said that because they weren't voting on each other directly, it wasn't definitive enough to call at the time (which is fair).
It's like half a week later now, and it's still going on. One will ask a question (poorly researched and contrived looking; not of high quality), then the other will answer (also usually not that high of quality), then they'll accept it. Then they'll swap.
They seem to be attempting to be smart about it to not trigger any detection, and they really aren't accumulating that much in the way of rep (one account is at ~100).
Should I care? I'm only interested because honestly I like trying to spot sock puppets. I find it interesting. The amount of rep involved is petty, and they'll likely never accumulate enough to gain any permissions or anything significant. It's still "rep fraud" though.
Should I reflag? Should I just let the system catch them if they slip up?
Mods ended up taking action on them without any further flags from me.