To be fair, most of the trades I've done from this forum went okay as far as the agreed to exchanges were concerned. I did notice that many traders did not ship their trade until they had received my trade and usually in the same box that I shipped my trade in despite my providing tracking info when I mailed the package. No big deal as I'm not some impatient mook who stands by the mailbox holding my breath until my latest trade/purchase arrives. However, I think you should disclose your intention to hold shipment of a trade until the other partie's trade arrives if you have trust issues or lack funds for boxes, etc just to reduce the potential for any aggravating surprises.
I heard a news announcer say (when reporting Berry's passing) that the building housing the Rock and Roll Hall of fame would house an IKEA or McDonalds today had it not been for Chuck Berry. I couldn't have said it better.
I have not been completely cheated out of any trades, i. e., I have always received the kit(s) offered in trade. However, I have received some kits in trade that were missing parts or had paint and/or assembly started which the trader did not disclose. I treated them as learning experiences since I didn't specify that I only wanted to trade for complete and unbuilt kits and I didn't ask if the kits offered in trade were complete and unbuilt when I negotiated the trade. I make a point of providing as accurate of a description of the kits I am offering for trade as possible and I assumed other traders did the same. It was disappointing and I felt kind of taken advantage of. I probably won't trade on this forum again in the future.