I have an idea. Find someone you can trust who lives fairly near you and willing to help. Then when someone untrusted buys a laser mail it to the middleman instead and have them then mail the laser to the buyer. That way the laser is put on tracking as sent and if a scammer reverses the payment while in transit to your middleman your only loss is shipping. The main cost to this method is you need a partner and your shipping costs will go up to buyers you are unsure of. You obviously wouldn't use the relay method for a buyer with massive rep but this way you can be way more secure with the little scamming dirt bags
Think of it as a "secured" shipping method and charge accordingly for the extra shipping costs and for payment to your middleman. Bam, good bye scammers.
Just a little idea of mine, might be more work than its worth idk.