Bump.
Tons of SPAM from Groups in the past month or so since some enterprising criminal(s) discovered that they can add any address they want to their spam groups w/out any verification or recourse.
There is no way to permanently "opt out" in these cases since the targeted e-mail addresses are not part of any Google account. I'm talking about dozens or hundreds of addresses... even if it was somehow practical to add these to a Google account (to then opt-out), I have no desire to give all this data to Google.
I'm no lawyer but I'm pretty sure being added to mailing lists w/out consent is actually illegal in at least in some jurisdictions.
I've submitted several "feedback" forms to Google on this subject now, with zero response.
Google, FIX THIS.