That process is typically part of the class action suit/settlement. It often comes with a binding agreement that by participating you are waiving your right to seek compensatory damages individually.
It world definately be hard to prove it. One would be purchases made while actively playing the game, and if you had an alibi by being at work or something as a parent, and the network/ip used to be purchase it doesnt match the network at work, at least the general area.
Yeah that a good alibi if it was purchased early and you can prove that you've been in the office at that time. What happens if it happen in the evening, and a lot of people are from home so its not a strong argument. Uterine what they'll do in this situation