Craigslist is the wild west. If you feel the seller is ignorant and will get taken advantage of by the local flipper patrol then feel free to reach out to them.
Reality is that there are probably 3 guys in every single major city with RSS feeds set up and they make a business out of screwing over iggnorant non-pinheads. For instance in our area there is this one guy Dustin from up in Appleton area, the scammer from rock island, and of course good ole Don in Verona, plus some guys in Rockford. These are the guys that also constantly run WTB ads on regional clist everywhere in a 500 mile radius.
I say screw these guys. I have warned sellers on clist before if i think they have put up something well below market value. Nothing wrong with being a decent person and letting them know that they should do their research before dealing with certain individuals or if they are way under priced. 99% of the time on clist you wont be screwing a fellow collector. You will be messing with the flippers that drive up your local scene.
When you are around long enough you will learn the patterns of these flippers. Some of them honestly have wrap sheets a mile long and is is worth warning an unsuspecting owner whom they may be dealing with. I know our local clist has had adverts against these guys on more than one ocassion from someone that got screwed over by them or had a bad experience on the buying end of a flip.