I worked as an accountant but I had nothing to do with payroll. One day I realized I could see the payment files from the payroll account so I did what any curious human would do, I exported the data and figured out what everyone's salaries were.
I used this information to negotiate a 15k pay rise plus 10% annual bonus. I never would have aimed so high and negotiated this without this secret knowledge.
It turned out if you worked for the company and had a penis you got paid well above anyone rocking a vagina. Because it was a smaller employer (<20 staff at the time) there were different roles, but if you compared degrees and time employed and technicality of the roles then there was clearly some favouritism toward males. This isn't even taking into account company cars were given to only men, who apart from a few, never needed a car for company purposes. It was just another benefit.
Once I got my pay rise my commitment to overtime vanished like a fart in the wind. My whole attitude shifted.
If employees, especially female employees, could have access to company payroll, there would be a huge shift in employer attitudes as we realize we are being taken for a ride.