I m not aware of our generally emailing people about scenarios.
I have done it in the past. Basically, took the list of e-mail addresses of registratants from the previous scenario and e-mailed them all about the upcoming scenario.
I ran into a technical snag of doing that, though, and with the new twins, it was one of the things that slipped off my plate.
It is a good idea to do it, I think, and I have never gotten a complaint back from anyone yelling at me about spam. Most folks either seemed to appreciate the notice or didn't mind getting one e-mail about it even if they didn't plan on playing in it.