ApplicationWillTerminate normal exit vs ad exit iPhone question

If there is no other / better means available, place a UIView over the ad area, detect touches on it, take a note, then pass it to the next responder (this is an ad).

In other words, you need a method that you can call to tell you that an admob has been added, and a UIView subclass that sits right above the admod view that has the following Began touches:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
     // you may want to do some extra work here to detect whether the touch is a 
     // touchUp in the view, vs. a touchUpOutside which is not the same.  It all
     // depends on how admob treats touches.  If it immediately quits your app on
     // touchdown, then you call your method immediately.  If admob waits to see
     // if there is a touchUp in its view, then you need to detect the same and
     // call your method after that.  Play around to see what you need to mimic.

    [self adViewHasBeenTouched];

     // The following is needed to let admob get the touch, after you are done
     // with your method.

     [self.nextResponder touchesBegan:touches withEvent:event];
}