What person to person marketplace is held to this standard? Certainly not Craigslist, eBay, or Fiverr. Arguably not even Amazon.
Craigslist completely nuked their personals sections because of the illegal activity on them, along with the resulting bad publicity and legislation that made it very clear what the standard is and that Craigslist needed to meet it.
They can't even be bothered to follow up on vendors dumping foreign country SKUs in the US and stomping on licensed frequencies. I got a nice letter from AT&T a couple months ago for a European SKU DECT phone from an Amazon listing that was confirmed to be the US SKU that I had purchased a few times prior. The order was even fulfilled by Amazon and they couldn't be bothered to check that the SKU on the box didn't match the product listing.