I just think that defining scams as simply, "convincing one to pay more than he should have for a product" to be not pragmatic. Sure all scams generally involve upselling (which I want to define as simply selling an item at a higher price than what the majority believes to be worth) but not all upselling involves scamming. For something to be considered as a scam it needs to involve a blatantly fraud and deceptive scheme. For someone to, for example, simply sell an item worth 500 tro in the market at a 600 tro price tag; making 100 tro profit, it cannot be considering as scamming.
If that is how you define as scamming than basically 90% of traders want to commit scams as they intend and wish to make profits at the trade place. The definition of scamming you present is not practical. This scamming you refer to is rather instead just the ingrain mechanic of the trade place where the market value of items fluctuate (generally involving perceptions that a specific item should be worth more than it is normally sold for, which then may then become the majority agreed upon price). This is why you often see items such as a new holiday shop sword spike up in price for a short period of time then come back down again.
What comes up in my mind when I think about scamming is the use of an item to deceptively cover the number items present on the table or the use of the trade table barrel glitch. Which now obviously interferes with one of the two partaking parties capacity of consent.
"The world is being much helped by the suffering of the poor people" -Mother Teresa
Spoiler
Who is Betray and what's going on?
Bring back pre trade table trading. People got hurt back then!