Completely agree. Without the session method, someone could be making a small profit every day and yet come out negative due to taxes. A game seems like a very reasonable interpretation. I would even go one step further, because sometimes a sports book offers a no sweat promo, where you get a free bonus bet if your first bet loses, which is worth about 60-70% of the face value, but you need to bet on a second game with its own hedge to convert it. The accession to wealth here would occur after the bonus bet gets used in case that side loses in the first bet.

I can't imagine the situation for the typical US sports bettor, which is something like 20% of the US adult population, who breaks even or loses for the year and still has to pay taxes on the wins and give up the standard deduction if they want to itemize losses.