Christ, controlling a meetup group is not where running a community ends.
As you suggest, I think the community belongs to the community.
Imagine if folks could buy abandoned Facebook profiles and be instantly connected to all their friends and groups/pages. I think most people would be against that.
At the very least I would hope to see a prompt or notification of some kind appear that says “hey, this community is under new management” and then I have to opt to stay in.
Also, you said two things interesting: "profiles of our old podcast producer meetup group", and then "without my input or opting in".
You used both "our" and "my". Do you see it as your group, or a group of people who have come together and could keep it going without you?
I think the only thing I can see that other members can't is:
1 Number of RSVPs
2 List of meetups attended
3 No-shows
4 Last visit to the Meetup page
5 Whether they are blocked from the group
Except for 3 and 5, the information is all available on pages visible to members anyway, though you'd need to page through all the past events to aggregate it.I do see a box "Get to know your members — With the Pro registration form, you can get key attendee details like email address and job title". I wonder where job title comes from, I certainly haven't provided that to Meetup. I'd also like there to be a way to hide my email address from Pro group owners, but I can't see one. Possibly I don't see the setting as I'm not a member of any Pro groups.
I wonder what all the differences there are. That would be more concerning if that allowed transfer.
If that value is more than a dump and run on the Meetup expense, there is an obvious arbitrage opportunity. Capitalism all but guarantees others will be able to leverage this along with the less obvious opportunities.