sidefx:
Most of his positive feedback seem to be for what look like low value items and some like they may have been negative originally changed to positive later... It's his history on buying computers that also worries me, especially the number of feedbacks he gets around getting abusive when things go wrong... Not that I'd be to bothered by that and i certainly would try and make it right if something did go wrong with the computer after sale. But, he just comes across as a bit of a fruit loop, and he would have my address after pickup, yeah i just don't need hassles from this if it goes wrong.
Trademe also allows removal of bids if you don't believe they're genuine so i asked them if i could do that in this case and they said yes. So... outcome is I've blacklisted and removed his bid.
Good call to keep your auctions hassle free. I tend to blacklist two groups of people: those who are dishonest (which is not necessarily measured by their feedback) and those who shoot from the hip because you cannot predict that they will think before acting.
Blacklisting is also used by traders who are dishonest or flexible with the truth. They limit criticism of their activities by blacklisting anyone who points out their deceptive or outright dishonest statements. That's why it can be worth checking out the Trade Me forums to see if a trader's auctions are mentioned or linked to there.