Well in my case (our case?) I'm usually dealing in something fairly obscure like an Imperial or a Mexican Ramcharger, not a '70 Charger which I'd assume is better bait. Not that it really proves anything, but it's something I guess.
I also draft a written contract that contains a copy of the title an each parties driver's license. In the case of both Mexican RC's, my California sellers (who were only advertising locally on CL) had Bank of America accounts. After. Of course I did some google snooping to verify their existence. We exchanged signed contracts, I deposited cash into their BOA accounts and arranged my own shipper. If they'd flaked, I at least had something for a local investigation.
Could it have been faked? I suppose. Then again, I bet I could create a fake pay pal account by the end of the day. Or a fake eBay account.
In the case of selling, I told each buyer up front that the cars don't leave until the cash is in my account. Which might have been 2 weeks (one was a check, the other was electronic). Neither objected. I used a business account in which I keep a super low balance (for tenants to deposit rent). In one of these, the buyer was Australian and wanted me to drop the car with Murray Park. (I offered because it's fun to drive old Mopars through Ohio.) I told him the car needed tires for that much of a drive. Went to my tire store on a Saturday morning, which I think was early Sunday in Oz, and had him call the tire shop and read off his CC#, accent and all. Gave me a chance to say "G'd day mate!"
All doable without a 3rd party getting a cut.