While brushing scams hint at a serious privacy problem for consumers, it's also a concern for sellers who may be bumped off their rankings because of competitors' boost in sales and positive verified reviews. The ubiquity of brushing scams is evidence of how important verified reviews and sales volume are to Amazon.

The caveat here is that betting on +900 underdogs often comes with heavy vig (longer odds tend to have wider markets) and that can cut into the free bet conversion. Let's say both of these lines are perfectly -110 balanced on each side – just like the coin toss.