There are a lot fo these settlement things that you can find on the internet--you have to affirm that you've bought Starkist tuna (or whatever product), but you aren't required to produce receipts, because the item is inexpensive, the time frame covered is long, and you likely wouldn't have a receipt for Starkist tuna from 2017 lying around. (Just picking on Starkist--obviously, it could be any product).
For larger, more trackable products, you would get a postcard--you bought a GE range in 2013 that's subject to litigation (again, just making this up). You sent in the warranty card, so they have your info.
Generally, these settlements have little value. They know a lot of people won't bother. Typically, you have a few months to submit your name, then the pot is split among respondees. You usually have a choice of $X off a future purchase, or $Y in cash/check. You eventually get a check in the mail for $1.20, or similar piddly amount. I'm still waiting on a tuna one that I submitted over a year ago (I think I asked for the free tuna coupons).
I can't imagine it would be worth the trouble to fake this to the tune of $150/month. That's a lot of lying (could face legal consequences), and a lot of trouble for the tiny checks involved. The real scammers are the lawyers involved with these lawsuits--they're making actual sums of money.
