Most communities don't accept sharking reports anymore for good reason because the definition of sharking is really to hard to define. Community A defines it as "A trade which user A lies to user B about the price" while Community B defines it as "User A rips off User B". The latter of which, has an ambiguous definition at best. For all we know, rips off can be defined with a scrap in difference or a bud in difference. What ended up happening in some communities is that some players started to report players who would "lowball" them as sharking which of course was annoying for any mods and traders. Again, it's hard to define what "sharking" really is. And then we get things like "quicksells" which further make sharking harder and harder to prevent.
Sharking is wrong. Let's leave it at that. Ripping a guy off for valuable items can't really be condoned. But it's just something you can't enforce because the definition is too ambiguous. Now I know the real world uses the universal commercial code which is like... nine articles long which lawyers can literally beat each other to death with, both verbally and physically, but who has the time to type that up? The real world's potential value in 26.9 nonillion or 26,900,000,000,000,000,000,000,000,000,000 dollars (this is an estimation) whilst the Tf2 economy in total is only worth about 16.9 million dollars. The massive difference in potential wealth will probably make the Tf2 economy... less serious. While I don't doubt people can easily benefit financially off the Tf2 economy, having known someone who brought himself a car by selling his backpack, the less serious means the "laws" of tf2 trade. Do people ever go to jail for stealing TF2 items? No. They just get banned from trading and/or marked as a scammer. Do people even get marked as a scammer for ripping someone off? No. The worst that happened back then was they got banned from certain communities, which most of said communities don't even accept sharking reports. That being said, sharking is going to exist. Here in TF2 and in the real world. How many times has some street vendor sold some really low-quality items for a bundle? Or how many times did someone selling a few thousand year old artifact from Mesopotamia had it brought for only fifty bucks? It happens everywhere and unfortunately, there's no way to stop it.