To save money, I send the item (usually a very small item of value) using a normal 1st class envelope, instead of a full package with tracking.

Sending with no tracking exposes me to the risk of the buyer receiving the item and claiming that he did not receive it which amounts to about a $20-$30 loss.

Since only around 1 in 20 or 1 in 30 buyers does this and based on the value of the items I sell, the savings from cheaper shipping (ballpark of $40-$60) offsets the few times that I am forced to offer a full refund ($20-$30) to the buyer for an item they actually received. I do acknowledge that from time to time, the USPS does indeed lose an item, but the percentages are so small, I consider them negligible.

When I report each buyer, I don't say that they were 100% scamming me. Maybe they truly misplaced the item or the item was truly lost, but by making a report here on
BadBuyerList.org , at least there is a record of such occurrences (assuming other eBay sellers report such instances), so if the buyer makes false claims habitually, the data will start to stack up against them. So my reporting this bad buyer is not saying with 100% certainty that he made a false claim, but the chances are pretty good.

In this case, he sent an eBay message to me saying he did not receive the item a week after it was mailed and without even giving me a chance to reply, he filed an eBay case. I sent him a message with a link to a YouTube video of my mailing the item and reminded him that with USPS Informed Delivery, each mail item is photo scanned at the post office, so any Postal Inspector investigation may show that in all likelihood the item was delivered to the mailbox. In this case, as soon as I sent him a message, he followed up and stated that he had already received the item (just today I assume) and he apologized for the inconvenience.