David,
I started collecting about a year ago, and I can understand your concern. However, my experiences have all been good with trades made with people posting on this board. In fact, in many cases, the person I've traded with has thrown in "a little something extra", like a lesser value chip or a slot card or a casino matchbook. Jill Bitner was the first person who did this for me and it made a big impression and I try to always remember to throw in something extra when I trade.
As far as conducting a safe trade, anybody serious about continuing in the hobby knows they can get a bad name very quickly if they don't conduct their trades fairly. You really can't conduct a trade by mail unless you have a little faith in the person on the other end. The whole key to building your collection is trading with other chippers, and trust plays a big part in the fact that there are so many trades and round robins going on all the time in this hobby.

In those rare cases where the person I'm trading with seems a little shaky, I just think about the value of what I'm trading. In most cases, since I'm not a high-dollar chip collector, it's not worth more than $10 or so, and I figure I can risk losing it if I get burned. (But that hasn't happened yet.)

Click the link below if you want to see what chips I have available for trade and e-mail me if you're interested.