[RobertD]

I just replaced my windshield and it had a pinprick like yours. Looking at simple fracture mechanics a "pinprick" (pinpoint) load like ours on a windshield will do more harm than a nice round pebble. That is why the emergency glass braking tools have a fine point on them - it allows a very concentrated "pinprick" load on the glass to shatter it.

This is what years of being an engineer analyzing broken stuff has done to me...