God this is so true. I won't say what company but it starts with W and rhymes with "they are very dumb" once brought myself and about 12 other contractors in to do a Windows XP to 10 migration project. It was a shit show.

First they told us this would be a project that required up to 90% travel as we would be going to multiple sites. I was a single guy with no pets so that sounded like fun to me. They eliminated a LOT of candidates because of that. The very first day it turned out that some projects had been mixed up so they had accidentally hired us into a contract with no travel and an entirely different team that thought they were doing a local contract came in on the same day to find out their contract was the travel one. Because of the way the contracts worked with pay, per diem, etc there was no way to just swap teams so after a few hours they fired the entire other team. They had to pay the contract agencies HALF of what they had originally estimated as early termination. Since those contracts were the more expensive contracts that meant the company essentially paid almost 100% of the value of the intended contracts and got nothing out of it. Day 1 hundreds of thousands, maybe upwards of a million, down the drain.

Then, they told us that our hourly rate would be cut by almost 30% because of the mix up but that we would be staying local. About 3 people walked out then and there, they also paid the agencies early termination on that.

THEN, it turned out that they had brought us in 4 WEEKS too early but they couldn't push it back because agency fees were racking up and it would be cheaper to pay us for 4 weeks of twiddling our thumbs then to pay more early term fees and find a new team. So they sat us all in a windowless conference room and told us to report in for 8 hours every day for the next 4 weeks while they desperately tried to get their shit in order. So, of course, we came in and did what anyone does in the course of being trapped in a windowless room with a bunch of strangers for 8 hours a day for a month, we pulled out our phones. Not 20 minutes later did the PM come in and tell us we couldn't use our phones. He was especially pissed at me for some reason because I had my PS vita out which I had bought because I had thought we were going to be traveling in airports and hotels a bunch. So we put everything away and we talked. About a day or two went by before we were told we were being too loud, so we whispered. That seemed to satify them for a few hours. Of course, being contractors we eventually talked about our rates. That's when we all realized there was a pattern. The men in our group were all being paid the same rate regardless of agency. The women were also being paid the same rate regardless of agency. However, the women were making $5/hour less than the men. We all agreed that was fucked up. One of the women had 10 years more experience than I did AND she had a degree whereas I did not. Not even an hour later we all got an email that we would have an emergency meeting with the PM. The PM came in to the cramped conference room but so did the director of IT and someone from fucking HR. We are then told that we are not allowed to discuss compensation or talk at all any longer and that we would be fired for doing so. Well, I was nieve. A few minutes after he left I did what I thought was right and emailed the three of them discretely and respectfully informing them that that was not legal and even linking them to the Department of Labor's site about the subject. About an hour later we were told that IT missed some updates to the laptops we had been issued. We were told to take them down to IT and pick them up again in the morning. Sure, whatever, everything else here is a shit show so why not that I thought. So, towards the end of the day we did that. By the time I got home I had a voicemail on my phone as did my parents who were listed as my emergency contacts on my contract forms that the entire team had been terminated, that I was no longer eligible for any future contracts with the company or the agency, and they added in the nice little tidbit that if I ever attempted to go back to their offices for any reason security would detain me and contact the police for trespassing.

I called lawyers, I called the news, I called the department of labor for my state. They all pretty much gave me the same answer, it was 100% an illegal termination but that proving it would be next to impossible because I would have to retain a lawyer, sue them, and hope that they comply with discovery and that the records showed explicitly that our contract was terminated because we discussed our pay rate.

TL;DR: Yes, labor laws in the US are little known and often ignored by giant corporations as I personally experienced.