Alternatively (and equally bad), upon seeing the karma has fallen, they might strive to post anything that won't be down-voted, but doesn't really add anything

Alternatively (and equally bad), upon seeing the karma has fallen, they might strive to post anything that won't be down-voted, but doesn't really add anything either, in the hopes of at least getting 1 vote to stem the tide. I can see this punishing infrequent, but quality posters and decreasing the signal-to-noise ratio. Sadly, somethings that work out just fine in math, don't mesh that neatly with human behavior.