Send mail without confirmation

I used to use phplist to send mails to all my NGO associaiton, but now with GPDR they have to accept before receiving the mails. Is there a way to send them mails unconditionally?

Thanks

To me, doesn’t that defeat the principal of permission based mailing, especially under GDPR?

I am allowed to send notifications about meetings to all the associates. It is a ~3.000 mail sent once a year.

I could use mailman, but it doesn’t allow throttle. I used to have a custom php script for this, but I started using phplist because of its throttling capabilities (and avoid bans).