Some of these threads are scaring me a bit.. But then someone has to be trusted at one point. Are group buys safer?
There are A LOT of people who prey upon new people, before they know what's going on.
There are people you can trust in the community, but it will take some time before you put together your mechanism to weed out the idiots.
Always be vigilant, even with people who pass your test - or have been vouched for by someone you trust.
Look at everyone with a suspicious eye.
Don't cut in front of people at Chipotle - I hate that.