When your company lays you off despite making record profits last year/quarter
The company I work for has a different strategy. They separated when reviews, and therefore raises and bonuses are given from the upper management to the lower level staff. Lower staff go first. When it comes time for lower staff raises and bonuses there's talk of 'tightening belts' and 'bracing for a recession' during communication meetings. A few months later when it's time for upper management it's 'Record profits!'.
Of course the lower level staff are given bonuses and raises based on those poor projections, while upper management gets theirs based on record profits.
If you keep your long term lower staff happy with very low raises and bonuses you not only save the money for your upper management in the short term, but also ensure that long term even a return to normal raises saves them money overall.
This is why I remind my coworkers that it is federally protected to share your wage and discuss it. They only get away with this if the long timers don't speak with the new hires and realize how badly they're being shafted.
The problem is that you basically need to have those conversations about wages in an email otherwise the company will still fire you for it, but claim it was just about "poor performance" or "insubordination" so they can't get in trouble for it... Hell I could even see a corporation arguing that your email conversation about wages wasn't "professional use of email directly related to their work" so there's pretty much always a way for them to skirt that law :(
Since I'm in an at will state that's always the risk, and HR will always lie to cover the ass of the company given the chance. But they still need people, and distributing that information only erodes their ability to keep people in the dark. They can't fire everyone that has spoken about wages in my case, we're simply too shortstaffed, and if I got fired I could be picked up easily by another company.
I know plenty of people aren't in that kind of favorable situation but it makes it easier to do the right thing. The bonuses I've seen our execs get would easily cover raises for the lower staff with room to spare.