You don't know what a fair salary is, because you don't know what your peers are earning. I mean, if you can find out what your competitors are paying their employees, surely their own employees can figure that out. So if you
can figure it out, it's not a secret to anybody!
The problem with your approach is that it is very easy to manipulate people when you permit a power/information differential like that. You end up saying "the slave is happy with the food we give him; why should we offer freedom?" -- when he's only happy with the food because you've been beating him for so long he's been conditioned into helpless appreciation of your scraps.
You feel you're making a fair salary? Well then what is the harm of knowing your neighbor's salary? Are you going to learn a new meaning of 'fair?' What's the harm in that? That's just updating your priors and giving you the ability to make better decisions with more information. (That anyone would choose to reject relevant information when making decisions is the height of absurdity.)