The problem with scalping is scale. A single person reselling a single ticket is completely fine, because that is not a viable business model for enough people to distort the market. Just limit the number of tickets someone can buy to 3-5.
Or they just hire other people to move tickets around.
It works at a small scale: 5 people, 5 tickets each, and $100 profit on each seat after everyone else gets paid? That's not so hard to keep track of, and it brings in $2,500.
It also works at a larger scale: 50 people. 5 tickets each, and $100 profit on each seat? Keeping that all in-line is definitely sounding like Real Work, but it also sounds like a tax-free $25,000.
Yes, but you can't know if the transfer happens at a profit. You can always ask the person to pay you extra on top of a "monitored" transfer.
UEFA limits this for football games by allowing you to purchase only two tickets and changing only one name, and the two tickets must go together. Or you sell back the ticket to the organization and they sell it back to random fans.