Ten years and twenty pounds ago, I worked on Wall Street. The pay was decent, the people were not. One of the downsides was that you had to sign an arbitration form to work anywhere that meant that if you were discriminated against or screwed over, you had to bend over again because you'd signed your rights to a trial away.
Basically, it boils down to this: You waive your rights to a trial and agree to have all disputes arbitrated. All decisions are final, no appeals. The fun part? Most of the arbitrators are paid by the firm you work for, so guess who usually loses? Right, the one who didn't pay. There's no public record like with trials, so companies can hide their dirty secrets. Sounds unfair because it is.
This practice is spreading and many more companies have joined the arbitration game. What do you do if a firm offers you a job but you don't want to sign? The offer will probably be rescinded. It's worth it to try and negotiate the terms of future arbitrations if you must sign. Ask if the firm will pay all the costs and try to get them to let you have a say in the pick of the arbitrator. Most likely it will be their way or the door, so only you can decide how badly you need the job and to throw away your rights.
Why are firms getting away with it? The same reason banks screw us, insurance companies don't pay and cheaters cheat. Because they can, because we let them. Because nobody stands up and says NO.