Worst case scenario mod is one who just-so-happens to be a irl-friend of a known troublemaker, thus giving the troublemaker a unique free pass. That happened on a forum I hung out some years ago. A well known troll, with delusions of grandeur, and "social experiments"-hobbies came to the forum. Many of us knew him from before, including some of the (otherwise quite decent) mods, and they banned him on the spot, before he could post more than a greeting.
Soon after, a specific irl friend of his mod unbanned him, and kept looking out for him. That spelled - no less than - the end of that forum. Only a few months later, the place was marred by a gulf between "camps", distrust between members and mods - both ways - everyone suspecting everyone of "mind-fucking" and manipulating.
Had I been a lesser person, I woulda danced around these people, chanting "TOLD YA SO! TOLD YA SO!", cus I was one of the goodie-two-shoes who tried to warn them, but was of course just dismissed as groupie trying to bed a mod or something "who do you think you are you turd pleb >:0"
I find NMA mods to do a good combination of getting involved in posting and the community, as well as keeping law and order. In fact, I came on here soon after the collapse of the other forum, and one of my first impulses was to check out mod behavior. Ya'll get an A+ and a smiley-sun sticker!