I do business on Craigslist. It is a great way to find local goods, and get better exposure for items you may want to sell. However...we must use common sense when advertising and selling.
If you have items like a couch or bedframe, these items should NOT be in your home for pickup. One PSP principle is...."Don't let strangers in." Yep. Just don't do it. It can make such transactions more difficult, but that is the cost of selling these things. They can be brought into the yard for inspection and sale. Yes...this is more work, but it needs to be done. Pictures and short videos can be shared to give potential buyers a good idea of what you have, but even then...don't show too much of the interior of your home.
Also, if you are selling expensive or very desirable items, meet your buyer in a very public place. The parking lot of a police station or fire department is a perfect location. Almost everyone knows these locations, so they are fantastic landmarks...and even the mention of them will discourage certain predatory behavior.
If you are considering the purchase of an item, the seller is aware that you will most likely have cash on you. The seller needs to be met in an equally public place. Those earrings are not worth a trip down a rural road! That car is not worth the risk of driving to a secluded location. Such transactions should be met with caution and preparation. A thoughtful "What if..." approach is necessary any time we deal with money and strangers. Cash is an extremely powerful motivator.
Keep doing business the way you choose...but make all of your decisions sensibly, and have a plan.
I'm busy working on my blog posts. Watch this space!