Perhaps it could show a reminder to have an email address in one's profile? That's recommended in general anyway

It would be more useful to have a button in each city to propose a meeting—no need to email anyone. You suggest a meeting, people can join or propose changes. That's it. :<

So everyone who signed up would need to check this site, is the idea?

Thank you!

Yes I would love to. I'll have to think of the best way to add this. If you have any suggestion please do share it!