While we have ability to configure SMTP batch sizes in Global Admin configuration, we don't have ability to check how many mail is going to send a survey.
This Feature Request asks for an option for controlling mailing before it's late.

A bunch of user stories:

As superadmin I want to block surveyadmins to send notifications to more than XXXX participants.
As superadmin I want to take in control mail sending when participants are more than XXXX.
As superadmin I want to be notified when surveyadmin wants to send notifications to more than XXXX participants.
As superadmin I want to configure XXXX number in global SMTP configuration.
As superadmin I want to inform surveyadmin about the limitation, in multilingual text.
As superadmin I want surveyadmin informed of XXXX limit before he tries to send notificaitons.
As superadmin I want to configure a custom message who overrides default multilanguage message.
As superadmin I want to inform surveyadmin with my custom message and not default multilanguage.