They've been doing this for a long time now, it sucks - Paypal are probably one of the worst companies I've ever dealt with.
There isn't much you can do about it, just make sure you add the tracking number to the transaction and make sure you send to the seller's verified paypal address,
In terms of spotting scammers, difficult these days - things I'd avoid would be;
In terms of the paypal hold - a little thing I learnt is this;
- People with zero feedback
- People with brand new accounts and feedback that all looks similar
- People bidding way higher than it's worth (happened to me once, turned out to be a 419 scam)
- People asking you to send to an address different than their registered paypal address (happened to a guy at work selling a 1080, buyer was using a stolen account
- Note the serial numbers on the item (to prevent a scam buyer from claiming it's broken, and returning their already broken product to you and keeping the one you sent)
Once it's showing as delivered on your tracking - ring the paypal call centre and tell them, in my experience they check the tracking number then release the money on the phone - however it's hit and miss (sometimes they do, sometimes they don't)
Adding to this, i would even avoid people with low amounts of feedback - it really doesn't take long to build up 5-10. And if all that feedback is all relatively new over a short space of time would raise some eyebrows.
Also make sure you're selling to a UK buyer, and offers from overseas i would avoid.
Yeah, that sounds like a massive pain in the ass.
Quite funny how they just gave up though, I always said to myself - I'd never pay if I was scammed in such a way, unless told to by a court - which in reality, over a few hundred or even few thousand - is probably never going to get that far, let alone lose.
Also not to mention you'd have a better chance of arguing your case (and to someone who would actually listen). As opposed to ebay/paypal being satisfied that an item broken/empty box received is clearly the sellers fault.