I have 30 or so hosts defined using 2 layers of inheritance. The parent template is: 
# Generic host definition template - This is NOT a real host, just a template! 
define host{ 
name generic-host ; The name of this host 
template notifications_enabled 1 ; Host notifications are enabled 
event_handler_enabled 1 ; Host event handler is enabled 
flap_detection_enabled 1 ; Flap detection is enabled 
failure_prediction_enabled 1 ; Failure prediction is enabled 
process_perf_data 1 ; Process performance data 
retain_status_information 1 ; Retain status information acro ss program restarts 
retain_nonstatus_information 1 ; Retain non-status information across program restarts 
check_command check-host-alive 
max_check_attempts 10 
notification_interval 0 
notification_period 24x7 
notification_options d,u,r 
contact_groups admins 
register 0 ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE! ---------------------------------- 
Then I defined a more specific template: 
#Parent Class that all objects will inherit from 
define host { 
host_name 58ants 
check_command check-host-alive 
notification_options d,u,r 
notification_period never 
max_check_attempts 8 
hostgroups Customers58 
name 58ant 
use generic-host 
register 0 } ------------------------------------------- 
by my calculations, I should not be receiving any notifications for hosts using this template. But I am and I don't know why. I'm using nagios2 on a debian etch system by the way.