Colorado recently passed a law, which supports the already in place, National Labor Relations Act, which says that employees have the right to discuss wages and benefits. The law will prohibit employers for taking action against an employee who discloses her or his pay.
You can read more here on the BLR website.
I suppose that in the seasonal industry wages are generally set and do not change much season to season, but do you have employees who try to stir the pot by sharing their wages with other employees? Have you ever disciplined an employee for talking about her or his earnings with other employees?