When you reach a settlement, you are deprived of the right to sue on the same grounds in the future. That is not unique to class actions. Class actions do affec

When you reach a settlement, you are deprived of the right to sue on the same grounds in the future. That is not unique to class actions. Class actions do affect the legal rights of a large number of people at one time, but that's typically necessary in cases where a large number of people suffered a relatively small harm, because otherwise the economics do not justify any individual to bring a suit. In fact, to have a case certified as a class action, you must prove to the judge that the class action format is necessary for plaintiffs to protect their rights. The judge also has to certify any class action settlement. And any member of the class may file an objection stating that the terms of the settlement are unfair. The judge reviews the objections (including to attorneys fees) and can reject them if the settlement is not reasonable for the class. On top of that, you do have to notify members of the class (by publication if they aren't individually known) of the terms of the settlement and give them instructions for filing objections before the settlement will be approved. This isn't to say that no class action is ever settled on terms unfair to the class, but there are a lot of protections to prevent that, and overall class actions are a valuable tool to protect consumers. That's why companies are increasingly trying to remove your right to join class actions by hiding terms forbidding it in EULAs and other fine print agreements.