Brian,
I don't think we should be trying to take a tutorial style approach
so much as making users aware that they need to find out how their
e-mail interface of choice can classify/declassify a given message as
being spam and what whitelisting is and that they should consider
using this mechanism for their e-mail interface of choice ...
I agree if the target "we" is all of Groups.io, meaning that I don't think the service needs to provide that level of Email 101 tutorial. Nor would I necessarily list that as a "best practice" for group management.
But I don't object if some group owners want to provide that level of tutorial for their members, and I would endeavor to help them do that where I can. In my PTA and alumni groups I pay far more attention to member contact and satisfaction than I ever would in any general email list or group. But that's because these are people I know and have occasional contact with in person. A special case for sure, but probably not extremely uncommon.
Shal
Shal Farley