Tying a session to an IP would be about the only reasonable solution, and even then, only
for the CB. In the end, it's really a matter of discretion; eat a little TROLL BAIT, and it'll be off your menu for a good long time, if not for good. Sentence structure, and style can help discriminate one, from another, as well as discerning intent. But IMHO, that's about it.
In the end, I think the tools PM already provides -- especially "peer review", do as good a job as anyone can hope for, and IMHO, a damn good job, at that.
¡λɐp ʇɑəɹ⅁ ɐ əʌɐɥ puɐ ʻꜱdləɥ ꜱᴉɥʇ ədoH