I'm having several troubles with Mailchimp plugin.
I did my tests with the 'Show subscribe to newsletters checkbox' enabled in the global configuration.
Here my troubles
- I have selected 'Double optin' option but I didn't receive any email asking to confirm Mailchimp subscription
- I have selected 'Add group members to newsletter' but the checkbox only appear for the billing member only (not for the other registrant) and the billing memeber was not added in the mailing list.