Paypal only covers you with full chargeback protections when you ship to the following locations: USA/Canada/UK (when you live in said zones). If you ship anywhere else, you're not protected against one of the criteria for chargebacks. Coupled with the fact that paypal already isn't very safe if the buyer is intent on cheating you, ebay is rife with fraud from overseas buyers who abuse the system.
That's ebay though. IF you trust the buyers enough here, tracking it, insuring it, and having them sign for it (and/or registering it) is enough. Your concern HERE is to just make sure it arrives and isn't damaged/stolen while in transit. The assumption on boards like this is that forum members won't actively attempt to defraud you.
I would personally feel safe shipping to overseas forum members IF they were willing to pay all of the shipping fees--and agreed ahead of time to pay any and all import/duty taxes/fees associated with that insured/declared value. In some places, that import can be up to 15%-20% on tech goods--though optical lenses are usually in the low 2%-5% category. If they refuse to pay the fees when presented with the package, it will make the long and slow trek back to you, doubling the odds of it being lost or stolen in transit. The full insured value and tracking is an absolute MUST.