It's tough at non-TCA meets where the buyers have little or no recourse. I was burned once a long time ago on an accessory and now do the following:
1) If the vendor is not a dealer with a brick and mortar store who's website you can visit to verify services, don't purchase engines or operating items unless a test track is available which is DCS or Legacy equipped (if needed for engines/operating items).
2) Even if a box is marked "New" or a vendor tells you an item is "New" ask to open the box to inspect the item. I had an experience even at York of someone misrepresenting an item.
Ebay, in my experience, is good at protecting buyers if an item is misrepresented. It may take 6 weeks but you will get your money refunded.
-Greg
