wait. you thought a seller was a "scumbag" because the rear hub on the bike he sold you was "shot"? what was wrong with it, and did he tell you it was perfectly smooth?
when i buy a bike from someone on craig's, they usually haven't a clue. i check the usual things, then take the risk. if i have to replace a 27" wheel (or its hub), it's not the end of the world. a cracked bb shell is something altogether different.
which reminds me ... i bought a $40 campy nr hub from an ebay seller that said he had overhauled it. when i got it, i found new grease. but i cleaned it out anyway and found the races were slightly pitted. he had lied about its condition, then again when i confronted him. i asked for $20 off the cost or a full refund. he gave me the $20.
i then sold it on craig's for $20 with full disclosure of the pitting. it probably built up just fine, but i require perfection in that sort of thing.
anyhoo, sometimes people know their stuff and aim to mislead. but more often, people are not as ... with it.