The maximum physical attendee capacity of an [Event](https://schema.org/Event) whose [eventAttendanceMode](https://schema.org/eventAttendanceMode) is [OfflineEventAttendanceMode](https://schema.org/OfflineEventAttendanceMode) (or the offline aspects, in the case of a [MixedEventAttendanceMode](https://schema.org/MixedEventAttendanceMode)).