They might be- though in Sac, the cops that ride around on bikes and ticket cyclists typically stick to the downtown business area, and I usually saw the BMXers in the surrounding 'midtown' residential neighborhoods. If they were doing tricks around downtown, they'd probably get chased out or ticketed pretty quickly.

Also, I wouldnt be as worried about brakes on a BMX- they're pretty easy to bail off of or slam your feet down on.

Edit: again, the 'money' angle is silly- at $25 a pop, I'm doubting that after a month, he generates enough money off brakeless fixed-gears to pay for more than food stamps for a family or two. He could make a lot more writing tickets for red-light runners, or the tons of people that ride at night without lights.