(I don't think spam flags are personalized, so even to me future emails wouldn't go to spam. I could set up a filter, though.)
EDIT: To clarify: in Germany you can sue companies for spam and making the opt-out unnecessarily difficult. Of course the damages are so trivial you'll likely overpay but there are enough bored lawyers that these things tend to happen every now and then.
I looked up the federal law at one point and private individuals had no rights beyond reporting to the FTC. ISPs may have standing if they can show harm.
See https://www.law.cornell.edu/wex/inbox/can-spam_standing and http://www.dwt.com/advisories/9th_Circuit_Deals_Blow_to_Prof...
I see now that the majority of this document could have expired. Not sure where to find these "notes" that the document talks about. It also says federal law would preempt. So yeah... talk to a lawyer I guess!