I'm glad to see some of the recent posts that emphasize the positive sides of Head-Fi.
Here are just a few examples that come to mind for me:
I've been a personal guest for overnight visits at the homes of at least 3 Head-Fier's (immtibiker, ServinginEcuador, and Todd), each of whom (along with their respective wives) treated me like royalty! Aaron and his wife have also spent a week with me here in Cayman. We trust each other with house keys, provide cars to drive, etc. On one trip, I practically moved in (9 nights I think it was!). Poor guy.
I've also received countless unsolicited offers from Head-Fi members, some of whom I've never met personally, to lend me gear. Some time ago, gplamer made an offer for me to be the caretaker (for a couple of months) of a rather expensive amp he owns simply because he thought I'd enjoy giving it an audition. Same goes for mrarrayo, who very recently made a similar offer (out of the blue) for a portable amp that he thinks I might enjoy. I've lent quite a bit of gear out myself, and 99% of the time, all goes well. It's always returned in pristine condition and with a note expressing sincere gratitude.
It's a great hobby that we have and the vast majority of people here at Head-Fi are indeed honest, trustworthy and "just like me" types of people (which is the way I try to evaluate any situations that arise in terms of buy and sell transactions). If you get an uneasy feeling about someone (for whatever reason) just back away from the deal. It's that easy.
Of course, nothing is iron clad, and there will always be risks. To me, it's a lot like lending money. Don't lend money to anyone unless you can be sure that the person you've lent the money to will follow through with ALL of his/her promises in terms of paying it back. If you perceive significant risks in terms of the amount, timing, or uncertainty of your future cash flows, then it's not a good deal for you to enter into no matter how much you might want to help the person in question. In that case, don't lend out more than you feel comfortable in losing.
Would I send out an expensive amp, source, or pair of headphones to a newbie? Probably not, unless there were other factors that really made me feel comfortable in doing so. But for old friends, sure, why not? For smaller (less expensive) items, it's not such a big deal, but like anyone, I absolutely hate it when I feel as though I've been taken advantage of. When you go out of your way for someone, it really sucks that they treat you like a fool and show no appreciation (or worse yet, steal from you).