There was a Planet Money story about this.
A company decided to make everyone's salary open knowledge, posted on the wall for everyone to see.
This would better solve gender pay equity than Pao's no-negotiation strategy. It puts more pressure on management to limit pay decisions to something defensable, prevents employees from pitting against each other for pay and minimizes management's ability to overpay or underpay. Employees know where they stand relative to other employees (and what they may need to do to make more). It motivates better paid employees to show they're worth it and makes it harder for well-paid employees to goldbrick.
The problem with no-negotiation is that for any given hire there are a finite number of employees available to take the job and the best candidate is likely to either be a little better or a little worse than average. Without the ability to negotiate, the better candidates will be less inclined to take the job because it only offers average pay and the below average ones will be more likely to take the job because it pays above what they're worth. You'll end up trending towards below average talent for more than they're worth.
Transparency allows for positioned to be negotiated for and if a given hire has an above average skillset and experience, you can agree to pay them more and won't have to worry about justifying it. The same is true the other way around -- it's justifiable to pay below average, too when you have legitimate reasons of skill or experience.
Pao's strategy is right out of the socialist playbook -- arbitrary price controls, and it destroys the free market's ability to seek efficient pricing. This isn't a political complaint, but an economic one. Most current job markets with "secret" pay agreements now are also bad because they create an imbalance between seller and buyer by eliminating pricing information.
It's also pretty sexist because it attributes a behavioral attribute to gender. I'm pretty sure Carly Fiorina, Meg Whitman, and other Fortune 500 CEOs don't have a negotiating weakness.