That's not double jeopardy - double jeopardy is a criminal law concept, and we're talking about civil lawsuits. You can be sued for the same act by multiple pe

That's not double jeopardy - double jeopardy is a criminal law concept, and we're talking about civil lawsuits. You can be sued for the same act by multiple people, though you can't be sued BY THE SAME PARTY for that same act multiple times under a doctrine called res judicata. You can usually opt out of a class action, and then sue again on your own - and you're entitled to your day in court to assert the claim against them. Though, since most people don't opt out, a class action does provide a way to settle the case with the vast majority of potential claimants. If the defendant LOST the earlier case, they may even be precluded from re-litigating any issues resolved in it (and, by extension, prevented from defending themselves substantively). Though in some situations, like if it were easy for the claimant to join the earlier lawsuit, this may not be so. See Parklane Hosiery Co. v. Shore, 439 U.S. 322 (1979).