Which is a vanishingly small slice of the sex worker pie (pun intended), and very, very few of those prosecuted are actually engaged in coerced activity.
Now, it's a great claim to make if you get caught because it's very hard for your pimp or coordinator to prove they weren't coercing you. You can angle for leniency from the system and stick it to your boss, and who doesn't like that?
At present, prosecution only requires the suspicion of trafficking, and that's an actual problem.