Yeah, that email is already sent out. If you have a different email address going to your phone, you should be able to set up email forwarding based on a subject filter for "OpenRaid - raid is starting soon!".
Alternately, adding calendar events to your phone will provide dynamic alerts based on your settings. Which plugs into this
suggestion, which I am very fond of.
I'm actually not sure what kind of infrastructure is required to be able for us to send thousands of automated texts a day, but I suppose it's something to look into for the future.