Hey Bob, thanks for getting in touch!
Oh man, sorry to hear that–I can imagine there were some pretty unhappy people waking up to a full inbox.
I’ve seen the Subscribe2 plugin but haven’t worked with it in depth. Does it offer a setting that saves an email as a draft before it is sent? That would allow you to review emails in advance and delete any that are unnecessary. Another idea might be excluding certain event categories from sending notifications, if the plugin offers those settings as well.
Unfortunately, Events are a type of post and I’m betting that the notification plugin you’re working with treats all posts equally, regardless if they’re set as a recurring event or not. That might be something to suggest to the plugin author, or keeping an eye out for a plugin that offers some more controls.
I hope this helps. Please don’t hesitate to let me know if I can be of further help.
Cheers!
Geoff