So, you get your check for $3.50 or a coupon for $20 off a new WD Red "NAS" drive from their web store. And then what?
Most people bought multiple drives at a time, spending hundreds of dollars. This seems like a prime candidate for technology-assisted small claims court, for the full purchase price of the counterfeit drives.
You do not need to get a non-trivial compensation for the threat of a class-action lawsuit to be a deterrent for behavior like this. It's the price the defendant pays that matters.
A coupon is a super bad deal because it doesn't punish the company. Trivial amounts of money are fine as long as it adds up to a huge number for the company involved. Think of it as more of a fine or a penalty to the company rather than getting your money back.
Even if all the money goes to lawyers, it's still a better deal for consumers than getting nothing.
Most people bought multiple drives at a time, spending hundreds of dollars. This seems like a prime candidate for technology-assisted small claims court, for the full purchase price of the counterfeit drives.