Would an opt out option in your settings be enough to satisfy you? As well as an additional rss feed that did not include meetups?
That way people can opt-out rather then requiring people to opt in to receive meetup notifications.
Would this solution be satisfying you? Do you think it would satisfy the community?
What techniques/methodologies do you use to divide techniques you approve of and those you disapprove? Stepping through this process with one of the techniques in the OP’s post would clear up much of why you would leave lesswrong if they became prominent.