If a lot of places required snail mail, you could charge to send that. Offer to do digital opt out free as a sort of trial. If there aren't many snail mail opt outs, then I don't see a way to make money from it unless you have it as a loss leader for a legal services automation company.
It seems more like part of a more comprehensive bundle of services to me, not something you’d offer solo. Maybe bundle it with a service that takes EULAs and generates billet point lists of their main points?