You are right, in an individual case like that, it's hard to make it a class action, but I'm sure there are plenty of cases where they get some bad data from so

You are right, in an individual case like that, it's hard to make it a class action, but I'm sure there are plenty of cases where they get some bad data from some vendor, and then promptly update 100k accounts with this bad data. Well that's 100k class action participants. :)