The only alt collateral I just had was stolen (see a couple posts up) due to my foolishness. The only collateral I have at this time aside from some older GPU mining hardware is my reputation here.
It was my fault for thinking someone was trying to help and not doing due diligence. I feel pretty stupid about it. I swear when I started here the community was not this theft-y (then again, coins were 10 or less and often people would send a quarter or a whole coin just to get users started, times change and so does BTC value! Now the scammers far outweigh the well wishers it appears).
Almost entirely my trades were made long before this Trust system was established. I've been here for a year and a half, give or take. Feel free to ask user "Projects" for verification of my reputation (as I've done countless transactions of various sorts with him over the past year), or search the "Honest Traders" thread for many feedbacks on selling/buying coin, as well as selling and buying hardware, since that is where the feedback used to allocate. I admit, I have not done a lot of trading within the "trust" system though I do have 4 ratings within it from other users (not sure why you didn't see them).
FWIW, I did one transaction with BitCoiner2012 a few weeks ago. My risk was ~.7 BTC I seem to recall. Transaction was flawless. Would trust again for future transactions.