OnStar Subscription

I'm not one to order extras in my car or phone or tv services.  So when I watch the commercials about OnStar on TV where they describe an accident and OnStar being there for you, I can't help but wonder what would happen if I didn't subscribe to the service.  It seems to me that OnStar would still know that my car was in a crash, and that I could be hurt.  But since I haven't paid anything, the operators ignore the "crash alert".  Is this ethical?  Have there been any cases where people have died while OnStar sat by and did nothing?