If there average payout is 5,770 per employee and the average salary jump while changing jobs is 10-20%.

The math is pretty in favour of having a wage conspiracy, thats without even considering the cost of not being caught.

Chance of being caught * average salary * cost of poaching * average salary rise due to poaching * number of employees / fine

Maybe my napkin math is wrong but the chance of being caught has to be very high and the average salary or number of employees very low for it to make any sense.

And being google and apple in california, the employee and salary is not gonna be low...

It definitely makes it worth it if you merely risk but are not guaranteed to lose about as much as you underpaid and avoid compounding increases.